Question

I added an attribute to a Core Data model (iOS). I was on version 2, so I added a new model and saved the new attribute under version 3.

My loading code is standard (initializing a MOM using initWithContentsOfURL: pointing at my .momd directory inside my bundle), then passing that MOM to a NSPersistentStoreCoordinator.

Then, I download my app from the App Store, run it, and then try to test the migration. Lightweight migration is working fine on my Simulator and my phone in Debug (tethered to Xcode 4).

However, when I sync a Release build (using the “Archive” feature on Xcode) using iTunes, my app’s data store fails to migrate with this error:

Error Domain=NSCocoaErrorDomain Code=134130 "The operation couldn’t be completed.
(Cocoa error 134130.)", reason=Can't find model for source store}

Worse yet, the store gets lost in some voodoo state where it cannot escape – if I re-tether the device and install a Debug build from Xcode again, I can’t “recover” the migration.

The error message above omits the details about my entities. I can provide that if helpful, but any ideas on what might be wrong here? I’ve read just about every question on SO about this error code and so far all of them have failed to produce a result.

I tried a manual migration, but it also yielded an error. However, since I only added 1 attribute to 1 entity, it doesn’t make sense that lightweight migration isn’t working.

Answer 1

Every time I’ve seen this problem, in my code or someone else, it has been XCode getting into some kind of bad state with regards to the model versions it deploys in the application. Open the Release IPA archive of your app, and look at what mom files are in it. If you see one of the previous versions missing, that is likely this same problem. As for a solution, I’ve had mixed results; some variation of the following steps works for me, but never in a consistent order.

• Clean & delete the derived data for the project (make sure you have an archive of your released app saved so you can symbolicate if necessary)
• Rename the previous model version files (in xcode), adding or removing the space between the name and the digit representing the version number (if it has a space, replace with ‘_’, if it doesn’t have a space try adding one)
• Add a new version of the model, without changing any of it’s content, and make it the ‘current’ version

I know these steps seem like grasping at straws, which is exactly what it feels like whenever this happens to me. You might consider using one of your support incidents with Apple, it would be nice to know what their official answer to this issue is.