After having installed the iPhone SDK 3.1.2, Interface Builder is not in sync with Xcode anymore. The light indicator at the bottom of the XIB window is grey. IB doesn't see any files from the Xcode project. Xcode is always open when I start IB.
I tried rebooting. No luck.
I tried removing the preferences files for Xcode/IB. No luck.
I tried reinstalling Xcode/IB. Still no luck.
This page explains how IB monitors the changes in Xcode. While it was an interesting read, it didn't provide any help about how to investigate my problem.
Any help would be appreciated.
EDIT
Here's additional information. I enabled the debug logs for launchd, and I noticed the following line that appears every time Interface Builder is started:
[0x0-0x1b01b].com.apple.InterfaceBuilder3[315]: Couldn't open shared capabilities memory GSCapabilities (No such file or directory)
This really seems to be related to my issue.
I have been having the same problem and it's been driving me nuts.
Bizarrely, it seems to be caused by opening your project using the File > Open Recent Project menu in Xcode, or by using the Recent Documents list in the Xcode welcome screen.
If I double-click the project file in the Finder to open it or choose the project from the Recent Items menu in the Apple menu, Xcode's connection to Interface Builder is intact.
Does that help you?