NSKeyedUnarchiver error after renaming Xcode project

I just renamed my Xcode project and when I ran it I got this error:

2015-11-14 05:32:42.337 Buck Tracker[3537:1456100] * Terminating app due to uncaught exception 'NSInvalidUnarchiveOperationException', reason: '* -[NSKeyedUnarchiver decodeObjectForKey:]: cannot decode object of class (iBudgeter.Record) for key (NS.objects); the class may be defined in source code or a library that is not linked'

The Buck Tracker is the new name and iBudgeter is the original name. Record is a custom NSObject I created to store some data.

I tried renaming the project back to iBudgeter but it didn't work. Reverting to a previous version in git did help but I got the same error when I renamed it again.

So any suggestions?

Don't change your project name. Just change the display name. It's the "Bundle display name" entry in your Info.plist. You'll probably need to add the entry.

See this answer if you want to change the display name of an OS X app.