Repairing “org.eclipse.mylyn.tasks.ui” Eclipse start-up freeze on Mac OSX

Excuse the shameless “fishing for a search string” title, but it just took me over an hour to find a fix for this so, so I’m paying it forward.

The problem

This issue appears as you start Eclipse after an incomplete shutdown on a previous session – i.e. if it was force closed. If you search for this problem you’ll see a lot of sledgehammer fixes suggested:

“Delete your workspace and reimport your projects.”

“Delete your metadata directory and reimport.”

“Delete all of the hidden files in your workspace.”


The very worst recommends completely removing Eclipse and starting again. To be clearย DO NOT DO ANY OF THESE!ย The solution is far too aggressive, and it loses your workspace configuration settings.

The problem occurs because Eclipse quits before it is able to delete a hidden “.lock” file in the workspace metadata. Upon restart it scans the metadata and sees this lock file, and as there is no pending task to clear it in the current instance, it awaits a deletion that will never happen.

The fix

Force quit Eclipse from the Dock if it’s still hanging; the damage is done, you can’t make it worse by closing it.

Open up Terminal, and navigate to the folder that contains your Eclipse workspace, then use this line to remove the hidden file lock.

sudo rm workspace/.metadata/.lock

Next, launch Eclipse with the clean and refresh arguments, so that the instance knows to regenerate any metadata that looks weird.

cd /Users/YOUR USER NAME/Development/eclipse/
./eclipse -clean -refresh

That’s it!

If you think that this might happen a lot (or if you’re just really into scripting for fun… What?) you can record the above actions as an automator script, and create a shortcut to it in your Eclipse folder so you can quickly repair the problem again in future.

The credit for finding this fix should go to sulai on, as I learnt about it from his comment on this thread, so do head over there and up-vote their answer if it helps you.

29 comments for “Repairing “org.eclipse.mylyn.tasks.ui” Eclipse start-up freeze on Mac OSX

  1. MingLiang Feng
    May 13, 2014 at 12:59 am

    Yes, this is the real solution.

  2. Rodrigo Rodriguez
    July 7, 2014 at 6:20 pm

    Awesome man! This worked for me! You’re a life saver.

  3. Rodrigo Moya Apablaza
    August 1, 2014 at 2:45 pm

    Thanks a lot for sharing! This save me a lot of hours of work.

    • August 25, 2014 at 6:09 pm

      Glad it helped!

  4. Lorenzo
    November 29, 2014 at 1:08 am

    Thank you, thank you, thank.

    • November 29, 2014 at 2:58 am

      You’re welcome, you’re welcome, YOU’RE WELCOME!

  5. December 11, 2014 at 5:33 pm

    Thank you for the “fishing for a search string” title. It paid off for me ๐Ÿ™‚

  6. barbazoo
    February 15, 2015 at 4:40 am

    Same issue happened under Luna. Deleting the .lock file did not help. I restored the prior version of the workspace/.metadata from backup. Thanks pointing out the .metadata source of the problem!

  7. David
    March 14, 2015 at 12:10 am

    Thanks, it really helps!

    • Johan
      May 7, 2015 at 8:42 am

      Neither solution worked out of the box for me…

      But the COMBINATION DID!! Just deleting .metadata/.lock still had me hanging at startup. And the Time Machine backup still had a .lock file in there. So I tried the combination: first restoring a backup (from a time I know I WASN’T in front of the computer to mess things up ๐Ÿ˜‰ ), and then deleted the .lock from the newly restored .metadata folder.

      Thanks!! It is MUCH better than re-importing all the projects back into the workspace, and then organising them back into working sets!! The past month(s) have been quite frustrating as I had to do it a few times. I even though it was because I moved my workspace to a separate drive.

      • Matt
        May 10, 2015 at 12:16 pm

        Glad that the information helped, even if it didn’t fix it for you right away.

        Thanks for adding what worked for you; will hopefully help others who have the same setup!

      • shai
        June 18, 2015 at 10:16 am

        can you please explain how you did it all step by step because I fail to do it the right way.

        • Matt
          August 4, 2015 at 4:47 pm

          Sorry, I’ve long-since abandoned Eclipse for IntelliJ, so don’t still have the software on hand to replicate this.

  8. Bharath
    March 26, 2015 at 10:47 am

    Real sol!

  9. Nishant Lakhara
    April 15, 2015 at 6:13 am

    Thanks a lot buddy

    • Matt
      April 28, 2015 at 12:00 pm

      My pleasure.

  10. Christopher McLeod
    April 20, 2015 at 2:16 pm

    Thank you so much! This was so frustrating and your solution worked like a charm!

    • Matt
      April 28, 2015 at 12:01 pm

      Happy to help! I’m amazed that they still haven’t fixed this issue over year later.

  11. taewoo kim
    May 15, 2015 at 1:31 am

    Thank you!!

    • Matt
      May 15, 2015 at 11:24 am

      You’re welcome!

  12. Sen
    June 10, 2015 at 5:38 pm

    Thank buddy. Saves my time !

  13. Ian
    June 13, 2015 at 12:11 am

    Doesn’t work in Luna… keeps hanging the same. This is just inacceptable and always happens when you need a critical fix, respecting Murphy’s law to the letter.

    What to do? the sledgehammer mindless solution? is software really that crappy in 2015?

    • Matt
      June 13, 2015 at 2:38 pm

      It does seem that software is getting worse lately… I just had to switch to Safari from Chrome to write this because it kept hanging after the latest update. Sorry to hear that it doesn’t work in Luna… I’ve switched entirely to IntelliJ now, and I’m not going back to Eclipse ever. It’s really a breath of fresh air using an IDE with some semblance of stability about it, with Maven support out of the box!

  14. Selim Ok
    October 27, 2015 at 7:43 am


    thank you very much. You saved my time ๐Ÿ™‚

    • Matt
      October 27, 2015 at 11:46 am

      I’m glad that you found it useful.

  15. Ronak Hingar
    February 28, 2016 at 10:58 pm

    I used to delete my metadata and then run it back . But this helps in figuring out the issue and saves hell lot of time.
    Thanks a ton ๐Ÿ™‚

    • Matt
      February 29, 2016 at 9:10 am

      Glad it helped! ๐Ÿ™‚

  16. Brian
    March 21, 2016 at 11:37 pm

    Chur, mate. Helped heaps

  17. Cristian
    May 16, 2016 at 7:51 pm

    Thanks!!!. Really worked!!!

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