1323

I'm trying to link a UILabel with an IBOutlet created in my class.

My application is crashing with the following error"

*** 
Terminating app due to uncaught exception
'NSUnknownKeyException', reason: 
'[<UIViewController 0x6e36ae0> setValue:forUndefinedKey:]: 
this class is not key value coding-compliant for the key XXX.'

What does this mean & How can I fix it?

11
  • 15
    pedrotorres is right. Yes this is right. If you are doing a UITableViewCell, in IB remember to make teh File's Owner to NSObject, and the UITableViewCell'Class to the .h class you defined.
    – gdm
    Commented May 24, 2013 at 7:56
  • 4
    When you encounter such an issue and the offending key is an action rather than an outlet then most probably you have an outlet which mistakenly references your action function name instead of your outlet variable name. Commented Jun 4, 2015 at 15:50
  • 2
    You should notice that the name of the key in the error message (the OP is calling it 'XXXX') is the name you gave to something in your nib file. That's should help narrow down your search.
    – kris
    Commented Jul 12, 2015 at 21:51
  • I filed rdar://22105925 asking Apple to make these errors more obvious at build time. :)
    – jtbandes
    Commented Aug 1, 2015 at 22:35
  • 1
    how to actually IMMEDIATELY SOLVE the problem! stackoverflow.com/a/13812660/294884 fantastic tip
    – Fattie
    Commented Sep 28, 2015 at 13:01

82 Answers 82

1671

You may have a bad connection in your xib.

I've had this error many times. While TechZen's answer is absolutely right in this case, another common cause is when you change the name of a IBOutlet property in your .h/.m which you've already connected up to File's Owner in the nib.

From your nib:

  1. Select the object in IB and go to the 'Connections Inspector'.
  2. Under 'Referencing Outlets' make sure that your object isn't still connected to the old property name... if it is, click the small 'x' to delete the reference and build again.

    enter image description here

Another common cause if you are using Storyboard, your UIButton might have more then one assignings (Solution is almost the same as for nib):

  1. Open your storyboard and right click the UIButton
  2. You will see that there is more than one assign/ref to this button. Remove one of the "Main..." greyed windows with the small "x":

    example 2

9
  • 2
    Thanks! In my case I had 2 outlets to the same view, and getting rid of the old one and hooking up the view to the new one ended the exception. Commented Feb 3, 2014 at 22:31
  • mine was duplicated twice. I began disconnecting each one after i dragged and dropped from a Pro version ( from a Lite version ) thinking it was hanging onto connections in the other project. When i came across the duplicate, and it took 3 clicks to make the disconnection, i sincerely wished i done that 3 days earlier. Oh well- such is the life of a dev.
    – aremvee
    Commented Jan 26, 2016 at 4:16
  • I had the problem that UIButton was having more than one assignings. This solved my issue. Commented Apr 17, 2016 at 16:07
  • I had this problem too. Don't forget to check outlet connections in particular views instead of only superviews. In my case, superviews weren't showing the wrong connections =/ Commented Sep 19, 2016 at 14:29
  • I had a similar error where I connected a button outlet to a the wrong ViewController swift file whose page would not have been created yet using the GUI
    – brw59
    Commented Feb 24, 2017 at 23:56
1065

Your view controller may have the wrong class in your xib.

I downloaded your project.

The error you are getting is

'NSUnknownKeyException', reason: '[<UIViewController 0x3927310> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key string.'

It is caused by the Second view controller in MainWindow.xib having a class of UIViewController instead of SecondView. Changing to the correct class resolves the problem.

By the way, it is bad practice to have names like "string" in Objective-C. It invites a runtime naming collision. Avoid them even in once off practice apps. Naming collisions can be very hard to track down and you don't want to waste the time.

Another possible reason for this error: when copying & pasting elements from one controller into another, Xcode somehow keeps that link to the original controller, even after editing & relinking this element into the new controller.

Another possible reason for this error:

Bad Outlet.

You have either removed or renamed an outlet name in your .h file.

Remove it in .xib or .storyboard file's Connection Inspector.

One more possible reason

(In my case) Extension of UIView with bindable properties and setting values for those bindable properties (i.e. shadow, corner radius etc.) then remove those properties from UIView extension (for some reason) but the following <userDefinedRuntimeAttributes> remained in xml (of foo.storyboard):

<userDefinedRuntimeAttributes>
  <userDefinedRuntimeAttribute type="color" keyPath="shadowColor">
      <color key="value" white="0.0" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
  </userDefinedRuntimeAttribute>
  <userDefinedRuntimeAttribute type="number" keyPath="shadowOpacity">
      <real key="value" value="50"/>
  </userDefinedRuntimeAttribute>
  <userDefinedRuntimeAttribute type="point" keyPath="shadowOffset">
      <point key="value" x="5" y="5"/>
  </userDefinedRuntimeAttribute>
  <userDefinedRuntimeAttribute type="number" keyPath="shadowRadius">
      <real key="value" value="16"/>
  </userDefinedRuntimeAttribute>
  <userDefinedRuntimeAttribute type="number" keyPath="borderWidthValue">
      <real key="value" value="0.0"/>
  </userDefinedRuntimeAttribute>
</userDefinedRuntimeAttributes>

Solution: Right click on foo.storyboard > Open as Source Code > search by keyPath (i.e. shadowRadius) > Delete the </userDefinedRuntimeAttributes> that causing the problem

16
  • 10
    Also do not forget to connect the "view" outlet of the nib to the file owner's view outlet (The view outlet of your custom class inherited from UIViewController). This can be done by control dragging from "File's Owner" under "Place Holders" to "view" under "Objects" and selecting the view outlet.
    – Nirma
    Commented Aug 11, 2011 at 14:49
  • 1
    I've made sure all the class are already set, but the NSUnknownKeyException still comes out :( Commented Apr 3, 2013 at 3:40
  • 1
    I'm not even using Interface Builder, and I'm still getting this error. Any idea what's going on?
    – sudo
    Commented Mar 9, 2014 at 7:18
  • 14
    Never mind. It was because of two things: Xcode was still accessing my Main storyboard even though it was removed from the project, and the simulator had it cached. I highly unrecommend using storyboards or NIBs – they're ridiculously problematic.
    – sudo
    Commented Mar 9, 2014 at 7:24
  • 7
    @Josh Lol. Everytime I work up the motivation to create a native app in xcode it always ends with me spending a day trying to figure out how to do anything. I'm a c# dev so I've been looking at offerings from Xamarin and Telerik (nativescript) lately. Commented May 13, 2015 at 15:02
158

Sometimes this has to do with your "Inherit From Target" That value has to be set. With single target apps you can just select Inherit From Target. If you have more then one target select the desired target.

enter image description here

8
  • This answer helped me for a specific case. I have to continu working on an old obj-c project with multiple target. I create a custom UITableViewCell in Swift and I had the same error. By enabling "Inherit From Target" it worked. Thank you!
    – magohamote
    Commented Apr 11, 2017 at 7:59
  • The module is not always set correctly; e.g. if you fill in the class name before actually creating the class.
    – Johan
    Commented Dec 22, 2017 at 10:45
  • I have filled the class name without pressing "Enter" key at the end so the IDE didn't checked this flag automatically. Wasted 1 hour on this. Thank you.
    – MatPag
    Commented Aug 17, 2018 at 16:20
  • Never encountered this type of error in obj-c. But thanks its solved the mystery. Commented Sep 13, 2019 at 6:57
  • why is this burried in the 3rd page?
    – Sergio
    Commented Nov 14, 2019 at 17:56
130

I had this error when I was trying to implement a custom ViewCell for a table. When I highlighted View controller for the XIB and connected to the elements in the CellView caused the error " this class is not key value coding-compliant for the key" once I deleted these it got rid of the error.

Delete the connections in the below image. Delete the connections in inspector when File Owner is highlighted

Just make sure that you only have the connections with the Table View Cell. To check click on table view cell and in INSPECTOR look for your connections.

The connection should be in here when Table View Cell is highlighted

5
  • 5
    This did it for me, thanks so much. I x'd out the connections when "File's Owner" was selected in the left column, then selected my custom cell and reattached them. Success!
    – Rogare
    Commented Dec 4, 2014 at 21:35
  • Even with xcode7 this works, just use the right panel "Connections inspector". Remove the outlet from the tableviewcell and from the label, then re-add it and everything should work.
    – lifeisfoo
    Commented Dec 30, 2015 at 8:28
  • 8
    This works but you need to make sure FileOwner didn't get set!! File owner should remain NSObject. stackoverflow.com/questions/13793162/…
    – devjme
    Commented Feb 27, 2017 at 15:32
  • The same answer saved me twice!
    – wm.p1us
    Commented Aug 20, 2018 at 9:23
  • 1
    Could someone please tell me what is the difference between set class name to File's Owner vs direct to UIView?
    – lee
    Commented Mar 31, 2021 at 4:38
124

I had to delete the app from the simulator/iPhone to get rid of this error.

5
  • 2
    +1 this fixed it for me. I was cleaning up some code that used IB. When I deleted a button from the code the error kept popping up even when this button was not referenced at all in the nib files (at least that I could see). Commented Sep 26, 2012 at 20:34
  • 2
    I find this is necessary if you are debugging two applications that happen to have the same name.
    – Anton
    Commented May 29, 2013 at 22:52
  • Yep, it seems that something from the XIB is cached on the simulator, which is a pain if you're testing upgrades since you actually don't want to have to delete the old app.
    – Carlos P
    Commented Jul 31, 2013 at 11:14
  • I had this problem deleting my XIB file. This fixed the problem.
    – balboa
    Commented Nov 25, 2014 at 17:17
  • 5
    If deleting app does not work, try deleting the XCode DerivedData folder. which can cache an incorrect xib file. Open XCode -> Preferences -> Locations -> Open the DerivedData folder and drag it to Trash. Commented Aug 18, 2015 at 21:05
68

If it is an iPhone only app, not a universal one, make sure the following field is empty:

Targets > Summary > iPhone/iPod Deployment Info > Main Interface

If you specify an xib there it crashes.

6
  • 2
    Yep, that was it for me. While flailing around to add a new startup view controller I set this to the new class/nib. After hooking up the view outlet I was hitting this error. Clearing this field fixed it. Commented Jul 13, 2012 at 23:55
  • This worked for me. Note that I also had to delete the old version from the device/simulator for it to work.
    – jimt
    Commented Oct 16, 2012 at 20:57
  • Thanks - this was my problem. I had renamed my iPad storyboard file and did not update in my project's prefs. Commented Dec 17, 2012 at 16:35
  • 2
    Thank you! This solved it for me. (I had to delete the app from the simulator after changing the Main Interface field to be empty. Simply changing that field didn't force the simulator to break the cache.)
    – snipe
    Commented Aug 31, 2013 at 8:32
  • I remembered that I changed things from a universal app to a iphone only app and this fixed the error!
    – Justin
    Commented Aug 6, 2015 at 14:22
64

This error indicates that an already connected Interface Builder object is removed/renamed in its owner's source (File's Owner).

Control-click on the Files's Owner in the Interface Builder if you see a exclamation mark you need to fix that.

In the picture below you can see that "aRemovedView" has an exclamation mark on its right, that's because I removed the IBOutlet view object while it was already connected in the IB.

enter image description here

This gives the following error: Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[ setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key aRemovedView.'

1
  • Thank you! This fixed it for me. I've been having this issue for a long time and didn't know how to fix it other than starting over from scratch. This was it, deleted IBOutlets from the view controller, but didn't know they were still referenced/linked in the owner (in this case "View Controller" in interface builder - Xcode 6).
    – Ira Herman
    Commented Oct 1, 2014 at 7:01
45

I had the same problem and while TechZen's answer may indeed be amazing I found it hard to apply to my situation.

Eventually I resolved the issue by linking the label via the Controller listed under Objects (highlighted in the image below) rather then via the File Owner.

Hope this helps.

enter image description here

42

in my case it was an error in the storyboard source code, follow these steps:

  1. first open your story board as source code
  2. search for <connections>
  3. remove unwanted connections

For example:

<connections>
    <outlet property="mapPostsView" destination="4EV-NK-Bhn" id="ubM-Z6-mwl"/>
    <outlet property="mapView" destination="kx6-TV-oQg" id="4wY-jv-Ih6"/>
    <outlet property="sidebarButton" destination="6UH-BZ-60q" id="8Yz-5G-HpY"/>
</connections>

As you see, these are connections between your code variables' names and the storyboard layout xml tags ;)

0
36

enter image description here enter image description here

My fix was similar to Gerard Grundy's. In creating a custom UITableViewCell using an XIB, I had mistakenly applied the Custom Class name to the File's Owner instead of to the UITableViewCell. Applying the class to the UITableViewCell on the canvas and connecting my IBOutlet properties to it solved the issue.

2
  • Ayyy dag nab it... Can't believe how often I make this mistake. Thanks lol
    – Benjamin
    Commented May 11, 2018 at 14:13
  • This also worked for me, but all the tutorials I watched say to set the file's owner to the class not the root view. I'm so confused on why this works in some cases, but not others? Commented May 24, 2023 at 19:10
34
  1. You only need to specify IBOutlet once, the IBOutlet label your ivar is unnecessary.
  2. Are you instantiating your NIB using your UIViewController? At some point you should be calling [SecondView initWithNibName:@"yourNibName" bundle:nil];
3
  • This helped! I was getting a key-value coding compliance error about a property from a different view controller. Turns out I was calling -initWithNibName with the wrong nib name.
    – jlstrecker
    Commented Oct 25, 2011 at 18:11
  • Yes this helped me too.. i was using the UIViewController instead of MyCustomeViewController.. but this is kind of hierarchy issue may be.. the introspection failed because of the miss placed class object.. Thank you anyways
    – Futur
    Commented Dec 12, 2011 at 5:38
  • I had a similar issue. Two identical IBAction entries by accident. Didn't show in the code, only in the right-click of the UIControl (A UIStepper in my case). Just deleting one fixed it. Commented Dec 9, 2018 at 2:42
32

This was happening to me only when debugging on a device (iPhone). The iOS Simulator was working OK. Doing a "Product->Clean" from Xcode seemed to solve the problem, but I have no idea why.

4
  • This solve my problem. tsk2x almost 3 days of headache. Commented Jan 29, 2015 at 3:06
  • 5
    It does provide an answer to the question. Something got messed up in Nib and doing a clean solved it. I read and tried all of the above to no avail and then did the clean, and after 1 hour of trying to fix it, Maj's solution fixed it. I would've loved to see what in the XML could've caused this but I've moved on. Commented Apr 8, 2015 at 18:47
  • This does indeed solve the issue - I tried numerous suggestions above and only did the project clean fix this error that suddenly started occurring. Ugg...
    – DustinB
    Commented May 12, 2015 at 5:03
  • This fix my problem, I tried lot of above suggestions. Seems strange! Commented Dec 29, 2015 at 5:30
25

It can come from the fact that you have control dragged and created an outlet or action, and forgot to delete it. Even if you deleted the code, or even if you have made enough cmd+Z, you'll need to go in the connection inspector of your storyboard and see if the action or outlet you created is still here or not.

1
  • Thanks! I'm a n00b on Xcode and took me a while to find the rogue links. In Xcode 9.2, you can right click on the element in the storyboard view and check the "Referencing outlets".
    – kunigami
    Commented Jan 22, 2018 at 7:00
24

I had exact same error message and thanks (!!) to Kira from http://www.idev101.com I was able to solve the challenge. I only found her site after googling and stacking over all these threads. I'm now posting here for the next one that comes to StackOverFlow and has the same challenge I had since that person will most likely come to this thread over Google.

I realized, that I wrongly made this:

UIViewController *deviceViewController = [[UIViewController alloc] initWithNibName:@"DeviceViewController" bundle:nil];

Instead of THIS:

DeviceViewController *deviceViewController = [[DeviceViewController alloc] initWithNibName:@"DeviceViewController" bundle:nil];

Where

DeviceViewController

Was the name of my Class also known as

DeviceViewController.h 
DeviceViewController.m

You'll have to

"import DeviceViewController.h"

in your implementation (.m File) where you want to call e.g. another UIViewController.

I am absolutely not sorry if I am only stating the obvious for beginners like me and may get down votes as this is not exactly related to the question but I was searching 4 (?!?) hours straight now for the answer to these error message. If I can spare this to 1 or 2 people that'd be great :)

PS: For those interested in how the code continues for loading the other UIViewController:

    [self presentViewController:deviceViewController animated:YES completion:nil];
2
  • THANKS for all the steps there, I was using Xcode 5 and didn't really know how to manually add a nib as you can only add storyboard by default.... I got some instructions but non as detailed as yours. Really helped!!
    – Pittfall
    Commented Oct 10, 2013 at 20:39
  • "I wrongly made this..." thanks, it's not the first time I spend a lot because of this really stupid mistake
    – tontonCD
    Commented May 15, 2019 at 14:36
23

Looking over the other answers it seems like there are a lot of things that can cause this error. Here is one more.

If you

  • have a custom view
  • added an @IBInspectable property
  • and then later deleted it

Then you may also get an error similar to

Failed to set (xxx) user defined inspected property on [Your Custom View] ...: this class is not key value coding-compliant for the key [xxx].

The solution is to delete the the old property.

enter image description here

Open the Identity inspector for your class, select the property name under User Defined Runtime Attributes, and press the minus button (-).

1
  • 1
    I came so often on this page... This time this solution made it! But as weird as it sounds the old property to delete was actually on another ViewController than from the one it crashes, i have no idea why.
    – Cinn
    Commented Apr 3, 2019 at 6:47
16

This happens to me when my view controller originally had an .xib file, but now is created programmatically.

Even though I have deleted the .xib file from this project. The users iPhone/iPad may contain an .xib files for this viewcontroller.

Attempting to load an .xib file usually causes this crash:

Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<UIViewController 0x18afe0> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key welcomeLabel.'

Solution when creating it programmatically may be this:

-(void)loadView {
    // Ensure that we don't load an .xib file for this viewcontroller
    self.view = [UIView new];
}
1
  • I had converted my tab bar app from .xibs to .storyboard scenes. When I tried to implement a tab that presented a custom tableview it crashed with "Missing proxy for identifier storyboardPlaceholder". After hours of trying to fix, I found this post. As soon as I deleted the original .xib (now converted to storyboard scene) file from the project, the app quit crashing when the tableview tab was selected. Commented Jun 29, 2021 at 18:15
13

"Module" property of View Controller in the Identity Inspector might be different than what you expected. Also make sure that new classes are added to your target list.

1
  • voting up since it was so in my case. I'm using Swift and Storyboards. When I created a new build target (to make a build variant) the app didn't work in the new variant while the first one worked OK. The app crashed on a View Controller where the module name was somehow set to module from the first target, while in working View Controllers it was Current - <module name here>. You need to erase the module name there in this case.
    – Mixaz
    Commented Apr 26, 2016 at 9:58
12

I had a similar problem for a project that has two targets (with their own MainWindow XIB). The fundamental issue that caused this error for me was that the UIViewController class wasn't included in the second project's resource list. I.e. interface builder allowed me to specify it in MainWindow.xib, but at runtime the system couldn't locate the class.

I.e. cmd-click on the UIViewController class in question and double-check that it's included in the 'Targets' tab.

0
9

Just to add to this, because I was getting this error as well. Going through all these answers most seem to apply to working with the UI and storyboard stuff. I know the original poster did seem to be working with the UI but when searching for possible reasons for this error mostly all questions lead back to this question with those others being closed as duplicates or simply having issues with connecting things in a storyboard so I will add my solution.

I was working on coding a web service in Swift 2. I had built all the needed proxy objects and stubs. As I looped through the returned XML I was dynamically instantiating my objects, which all came from NSObject and using setValue:forKey on them. Every time setValue:forKey tried to set a property it blew up with this error.

I had a switch statement for each type I was dealing with (e.g. Bool?, CShort?, String?) and for each XML node I went through and checked what the type was on the object and then converted the value to that type and attempted to set it with setValue:forKey.

Eventually I started commenting out all these setValue:forKey lines and found that my default switch statement case did work for String?.

I finally figured out that you can't use optional swift types with setValue:forKey unless they have a direct mapping to an Objective-C type like String? or NSNumber?. I ended up changing all CShort? types to NSNumber? since that has a direct mapping. For Bool? in my case it was fine for me to just use Bool and initialize it to false. Others may not have that luxury.

Anyway what a headache that was so hopefully this helps someone else who has a similar problem and keeps getting redirected to this question and saying to themselves, "I am not doing anything in UI!!".

So lastly to reiterate one more time Key-Value Coding does not work with optionals. Below I ended up finding somewhere but I forget where so to whoever posted this I apologize and would give credit if I remembered where I found this but it saved my life:

You cannot use KVC on an Optional Int property, because KVC is Cocoa / Objective-C, and Objective-C cannot see an Optional Int - it is not bridged to Objective-C. Objective-C can only see types that are bridged to Objective-C:

class types that are derived from NSObject

class types that are exposed with @objc

Swift structs that are bridged

1
  • 1
    If you are trying to connect a Swift bool value via Cocoa bindings, you need to expose it with @objc directive; otherwise you indeed get this error. This should be the best answer.
    – jvarela
    Commented Jul 26, 2019 at 0:01
9

"this class is not key value coding-compliant for the key" I know its a bit late but my answer is different so I thinks it needs to be posted, I was pushing the second controller in wrong way, Here is sample

Wrong Way to Push Controller

UIViewController* controller = [[UIViewController
 alloc]initWithNibName:@"TempViewController" bundle:nil];
         [self.navigationController pushViewController:controller animated:true];

Correct way

TempViewController* controller = [[TempViewController
 alloc]initWithNibName:@"TempViewController" bundle:nil];
         [self.navigationController pushViewController:controller animated:true];

I did not found any answer like above so may be it can help some one having same issue

8

That might be the case of referencing a component from Xib Interface that you have renamed or delete. Re-referencing works for me.

8

I just had this issue in my duplicated project and solved by checking 2 places:

1- Make sure you have the .m file in the list -> Project - Build Phases - Compile Sources
2- After that, go to interface builder (probably this is an error occures with only IB) and unlink all properties, labels, images, etc... Then re-link all. I have realized that I've removed an attribute but it was still linked in IB.

Hope it works for some.

7

Another "not compliant" issue I found was when I managed to have two copies of a class for some reason.

I was adding keys to the wrong copy. Interface Builder still saw the keys and let me hook up to them, but at runtime it was using the other copy of the class that didn't have the new keys.

To find which was the "right" copy I used XCode's cmd-click on the class name elsewhere to jump to the correct copy, then I killed off the bad unused copies (after bringing over my edits from the un-used copy first).

Moral of the story: duplicate class files are bad.

0
7

This error is something else!

Here is how i Fixed it. I'm using xcode Version 6.1.1 and using swift. I got this error every time my app tried to perform a segue to jump to the next screen. Here what I did.

  1. Checked that the button was connected to the right action.(This wasn't the problem, but still good to check)
  2. Check that the button does not have any additional actions or outlets that you may have created by mistake. (This wasn't the problem, but still good to check)
  3. Check the logs and make sure that all the buttons in the NEXT SCREEN have the correct actions, and if there are any segues, make sure that they have a unique identifier. (This was the problem)
    • One of the segues did not have a unique identifier
    • One of the buttons had an action and two outlets that I created by mistake.
    • Delete any additional outlets and make sure that you the segues to the next screen have unique identifiers.

Cheers,

7

In my case. I didn't have missing outlets in xib-files after merging.

Shift + Command + K

solved my problem. I cleaned my project and rebuilt.

6

I had the same symptom. The root cause was that the "Target Membership" for my source file was not set to the correct target. I assume that means my class wouldn't get built and included in my app.

To correct it:

  1. Highlight your .m file.
  2. In the right pane, select the File Inspector.
  3. Under the "Target Membership" section, make sure the appropriate build target is checked.

Hope this helps somebody out there.

6

If you have a custom UIViewController subclass with IBOutlets that are causing problems the only set of steps I found to actually get rid of the error were

.1 Change the class to UIViewController

.2 Disconnect all the outlets (they will all have the yellow warning triangle now) - it may be enough just to disconnect the problematic outlet(s).

.3 Do all the standard steps - ↑⌘K, delete Derived Data (, prayer mats, worry beads)

.4 Launch the app - go to the problematic scene.

.5 Kill the app, go back to Interface Builder change the class back to your custom class name.

.6 Reconnect your outlets.

Launch the app & this will normally have cleared up the key-value compliance issues.

1
  • This worked when copying and pasting a scene in the Storyboard editor.
    – Mizmor
    Commented Apr 25, 2019 at 18:31
6

In my case it was the module that was specified to the wrong target. Simply deleting the module name and checking Inherit Module from target did the trick.

enter image description here

0
4

In my case, this was caused by referencing the wrong Nib:

BMTester *viewController = [[BMTester alloc] initWithNibName:@"WrongNibName" bundle:nil];
1
  • 1
    Happens to me when I rename the view controller's class and forget that the the nib name needs to change too. Since the nib name is just a string, there's no compiler error.
    – kris
    Commented Jul 12, 2015 at 21:47
3

I was getting this error with storyboards. The above solution didn't seem to be the problem so I ended up deleting the view controller and adding it back in again (and of course reconnecting the segue and reassigning the class) which fixed it. I don't know what it really was, but I had renamed the associated view controller class shortly before this started, so maybe that had hosed something.

1
  • I got this error again. This time I created a new empty table view controller with my class assigned to it, leaving the non-working one alone, and moved the segue to it. This worked. I then slowly copied every element in the view over until it failed again. This time the problem turned out to be I had assigned some "User Defined Runtime Attributes" for a picker (I was thinking I could use them to initialize the picker so I wouldn't have to do it in code, no idea if that's possible). Removing that fixed the problem. This error is really horrible, I hope it's improved in a future release!
    – Symmetric
    Commented Jan 7, 2012 at 4:39

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