Save Core Data models in Xcode 4

I want to create a new split view-based iOS project from scratch开发者_开发问答 using the template wizard of Xcode 4.0 (build 4A304a). I ticked the "Use Core Data" checkbox. When I try to save the generated test.xcdatamodeld Core Data model, Xcode says The document "test.xcdatamodel" could not be saved.

How can I save the file? I already checked the file system for the proper permissions, but they seem alright.

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Aha - I've been suffering from this problem all day and just found the answer. I ran /Applications/Utilities/Console and tried the save again. This error appeared in the console:

AppKit called rmdir("/Users/kris/.TemporaryItems/folders.501/TemporaryItems/
  (A Document Being Saved By Xcode)"), it didn't return 0,
  and errno was set to 66.

Though I couldn't see anything obviously wrong with this folder (the permissions & ownership looked normal), removing the whole of ~/.TemporaryItems/ allowed me to save again.