User Operation is waiting for "Building Workspace"
I had exactly the same problem. For me helped adding '-clean' option at the first line of eclipse.ini file and restarting IDE. After adding this option eclipse clean all cached data in workspace each time it is started (that also mean it will be starting slower).
You can find more information about it here: How to repair hanging 'User Operation is waiting for “Building Workspace”' in eclipse
For me the clean option didn't work and I didn't want to reset the workspace. Fortunately for me another solution worked:
- Disable automatic builds (uncheck menu item Projects -> Build Automatically)
- Restart IDE (I had to kill it from command line)
- Close all projects
- Restart IDE (this time it should close without problems)
- Open projects that you need to work on (everything should be fine now)
Oh yeah, I had the clean option in the eclipse.ini the entire time. Not sure if that is necessary, but it might be good to try that option first anyways.