|"The document "LoginWindowUI.nib" could not be opened. Interface Builder cannot open compiled nibs. Try opening the source document instead of the compiled nib."|
- First, download and unzip this, which has dummy versions of both needed files.
- Right-click on the file you want to edit and choose "Show Package Contents".
- A new window should come up, and there will be one file, keyedobjects.nib, listed.
- Copy classes.nib and login.nib into this folder.
- You should now be able to open the original .nib file.