When I perform a merge between 2 branches, and get a conflict on a file, I try to resolve the conflict with the option "launch external merge tool" which starts Tortoise Merge.

In this program I can resolve the conflict and save the progress. When I exit the merge program, SourceTree crashes. After restarting SourceTree the file is marked as merged successfull.

The crash report gives this exception:
System.NullReferenceException was unhandled
Message: An unhandled exception of type 'System.NullReferenceException' occurred in SourceTree.Api.UI.Wpf.dll
Additional information: De objectverwijzing is niet op een exemplaar van een object ingesteld.