Sourcetree won't start

After clicking on it no GUI will open. It uses some CPU and Logs this. 


ERROR [2017-10-16 18:37:09,072] [1] [SourceTree.App] [.ctor] - finish EnsureSquirrelExecutionStubIsCopied
ERROR [2017-10-16 18:37:09,337] [1] [SourceTree.App] [OnStartup] - Failed to start
System.NullReferenceException: Object reference not set to an instance of an object.
at SourceTree.Notifications.NotificationsManager.SetOwner(NotificationDialogWindow notificationWindow)
at SourceTree.Notifications.NotificationsManager.ShowNotificationDialog[T](NotificationDialogWindow notificationWindow, Tuple`2 customAction, VistaTaskDialogIcon icon)
at SourceTree.Notifications.NotificationsManager.ShowNotificationDialog[T](String title, String message, Tuple`2 customAction, String cancelLabel, String suppressionSetting, Action`1 suppressionChangedAction, Object contentControl, String contentCommandLabel, Action contentAction)
at SourceTree.Notifications.NotificationsManager.ShowNotificationDialogWithYesConfirmation(String title, String message, String details)
at SourceTree.Configuration.WpfSpellCheckerPreFlightCheck.Run()
at SourceTree.AppRoot.RunPreFlightChecks()
at SourceTree.AppRoot.OnStartup(StartupEventArgs e)
at SourceTree.App.OnStartup(StartupEventArgs e)

3 answers

1 accepted

1 vote
Accepted answer

Hi Mahdi, you can find the solution in this other Community thread, it's the answer proposed by Mike Corsaro:

Please navigate to the config file location (C:\Users\{USERNAME}\AppData\Local\Atlassian\SourceTree.exe_{RANDOM_GUID}\\user.config) and find the following line:

<setting name="AutomaticallyCleanUpDictionaryFiles" serializeAs="String">



Make sure that value is set to True

Let us know if it worked for you!



Wow. Thanks for your fast replay. I do not have such a thing as in answer. And as I didn't think someone answers this fast, I uninstalled it, truing to reinstall and see if it works.

<setting name="AutomaticallyCleanUpDictionaryFiles" serializeAs="String">

Thanks Ana, that did the job for me too, although as Mahdi Rafatjah stated, i didn't have that option either.  I added it manually.

After that i executed sourcetree again and it completed its installation/configuration.


btw, I am using windows 10 pro.

Had the same problem with the exact same error. I had no setting like this in my config file. You have to add it manually, and it works.


Atlassian : Can you publish a fix for this ? It's a critical bug and I lost a lot of time trying to resolve this.

Hi @Francois BERTRAND, this issue was reported in our issue tracker at SRCTREEWIN-8046. Also, it's been asked in our Community multiple times, so the solution is also posted here publicly.

We have just started the progressive rollout of Sourcetree v2.3.5.0 which includes a fix for this issue. You should be prompted to upgrade sometime over the next 14 days or, alternatively, you can download theupdate directly here:

Hope that helps!


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