# Unable to perform work on main run loop, process main thread busy for 2.0s - recommend retry by client

**URL:** <https://discuss.bitrise.io/t/unable-to-perform-work-on-main-run-loop-process-main-thread-busy-for-2-0s-recommend-retry-by-client/2556>\
**Category:** Question & Answer\
**Tags:** xcode\
**Created:** [August 24, 2017, 10:26am UTC](https://discuss.bitrise.io/t/unable-to-perform-work-on-main-run-loop-process-main-thread-busy-for-2-0s-recommend-retry-by-client/2556 "2017-08-24T10:26:04Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![blackjacx1](https://avatars.discourse-cdn.com/v4/letter/b/8e8cbc/32.png) [@blackjacx1](https://discuss.bitrise.io/u/blackjacx1)\
**Post date:** [August 24, 2017, 10:26am UTC](https://discuss.bitrise.io/t/unable-to-perform-work-on-main-run-loop-process-main-thread-busy-for-2-0s-recommend-retry-by-client/2556/1 "2017-08-24T10:26:05Z")

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I implemented the new screenshot tests of Xcode 9 and they often fail on bitrise when 2 integrations are running in parallel with the following error message:

```
Executed 66 tests, with 0 failures (0 unexpected) in 5.126 (5.197) seconds
Quick.framework
All tests
Test Suite BeiwagenUITests.xctest started
ScreenshotUITests
✗ testScreenshotApp, Unable to perform work on main run loop, process main thread busy for 2.0s - recommend retry by client
BeiwagenUITests.ScreenshotUITests
testScreenshotApp, Unable to perform work on main run loop, process main thread busy for 2.0s - recommend retry by client
<unknown>:0
Executed 1 test, with 1 failure (0 unexpected) in 53.847 (53.851) seconds
Failed to update screenshot names, error: screenshot not exists at: /Users/vagrant/Library/Developer/Xcode/DerivedData/Beiwagen-fkftxgyqzutwhfgakscnfpopktat/Logs/Test/Attachments/Screenshot_64ECA6ED-9C8F-438B-A88E-83CFC060F616.png
xcode test exit code: 65
xcode test failed, error: exit status 65
If you can't find the reason of the error in the log, please check the raw-xcodebuild-output.log
The log file is stored in $BITRISE_DEPLOY_DIR, and its full path
is available in the $BITRISE_XCODE_RAW_TEST_RESULT_TEXT_PATH environment variable.

```

The XCUITests do NOT use any 3rd party libraries.

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<div class="post-metadata">

**Author:** ![blackjacx1](https://avatars.discourse-cdn.com/v4/letter/b/8e8cbc/32.png) [@blackjacx1](https://discuss.bitrise.io/u/blackjacx1)\
**Post date:** [August 25, 2017, 2:33pm UTC](https://discuss.bitrise.io/t/unable-to-perform-work-on-main-run-loop-process-main-thread-busy-for-2-0s-recommend-retry-by-client/2556/2 "2017-08-25T14:33:11Z")

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Anybody an idea?

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<div class="post-metadata">

**Author:** ![godreikrisztian](https://sea2.discourse-cdn.com/flex016/user_avatar/discuss.bitrise.io/godreikrisztian/32/22_2.png) [@godreikrisztian](https://discuss.bitrise.io/u/godreikrisztian)\
**Post date:** [August 28, 2017, 8:37am UTC](https://discuss.bitrise.io/t/unable-to-perform-work-on-main-run-loop-process-main-thread-busy-for-2-0s-recommend-retry-by-client/2556/3 "2017-08-28T08:37:05Z")

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Hi @blackjacx1,  
sorry for my late response, could you please write us on [bitrise.io](http://bitrise.io) on-site-chat? i would need to take a look on your full build log file.

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**Author:** ![viktorbenei](https://sea2.discourse-cdn.com/flex016/user_avatar/discuss.bitrise.io/viktorbenei/32/18_2.png) [@viktorbenei](https://discuss.bitrise.io/u/viktorbenei)\
**Post date:** [September 5, 2017, 9:38am UTC](https://discuss.bitrise.io/t/unable-to-perform-work-on-main-run-loop-process-main-thread-busy-for-2-0s-recommend-retry-by-client/2556/4 "2017-09-05T09:38:43Z")

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@blackjacx1 did you manage to solve the issue? If not, can you please copy the link/url of the build here, or contact us through the onsite chat on [bitrise.io](http://bitrise.io)?