Eclipse hangs at the Android SDK Content Loader

This is the solution I found which works correctly:

1. Make sure that eclipse is not active. If it is active kill eclipse from the processes tab of the task manager
2. Open %USERPROFILE%/ on Windows or simply ~ on Linux/OS X (You can locate this folder from the Desktop)
3. Go to .android folder (This may be a hidden folder)
4. Delete the folder cache which is located inside .android folder
5. Delete the file ddms.cfg which is located inside .android folder
6. Start Eclipse

Hope that this will work for you.

Same problem, stuck at 0%. Ran

/Applications/eclipse/eclipse -clean

and everything worked great again. Modify that path for linux boxes.

Update (from the remark from @Janusz )

For mac users with eclipse outside application directory your clean command will looks similar to:

path/eclipse/Eclipse.app/Contents/MacOS/eclipse -clean 

Go to your workspace directory \workspace\.metadata\.plugins\org.eclipse.core.resources\.projects and delete all the projects in there.

Note: You are not going to lose your projects

I have used some other answers here to fix this problem but I came across it again recently, and none worked. I didn't want to re-install or delete my workspace, so I finally found one that did work that might help someone else. Delete the file:

/workspace/.metadata/.plugins/org.eclipse.e4.workbench/workbench.xmi

You can make a backup first, if you like. It stores your workbench settings (perspective state, file paths for menu options, etc.) But eclipse loaded and I didn't have to re-install anything like some answer suggest. And I haven't seen this anywhere.