Couldn't load a xcode project because it is already opened from another project or workspace

I have a project that has one target dependency. The target dependency is dependent on a framework called Three20.

The dependency tree looks like this.

开发者_如何学GomyProject
   -> myCustomFramework
         -> Three20

When I tried to build and run I get the following error message.

Workspace Integrity Couldn't load Three20.xcodeproj because it is already opened from another projet or workspace.

I have only one project open. Any suggestions on why I am getting this message?

Quitting the xcode completely and opening it up again worked.

Quitting Xcode alone didn't work for me. What I did was:

1. File->Close Workspace/Project on every open workspace.
2. Xcode->Quit
3. Open Xcode again and open troublesome workspace

I have close the Xcode completely but IT didn't work. I have killed the procces and It did finally!!! :-)

Had the same problem in a case where I got a workspace working, closed it, copied the containing folder to a USB drive, then reopened. I got that message for one of the projects in the workspace. Closed, tried again, removed/re-added project - no luck. Closed, tried to open the project alone and got the message about it being open in another workspace - not true. Quit XCode, restarted by double-clicking my workspace in Finder, and all went well after.

I had same problem. Fixed after updating of cocoa pods with pod update command.

Restart the computer and try again opening the project :)