Xcode project not working after replacing project folder

Question

I was working on an xcode project called Test, which I then made a copy of the project folder as a backup. Now , I would like to replace my current Test project with my backup folder, which I did. But now I seem to be having errors like:

_OBJC_IVAR_$_GameLayer.backgroundSheet", referenced from:
      -[ALayer setBackgroundPosition] in ALayer.o

backgroundSheet existed in the newer version of my project, which I have replaced. Why is Xcode still reading it? Thanks!

Edit: When I open my backup project which is in a different location it works fine.

Answer 1

Clean your build using Product -> Clean (shift + cmd + K), and after this build. It should help.

Answer 2

Are you using xcode 4.2 and if you opened both projects (backup and working copy) at the same time you will get error like this