Problems with Sourcetree: resolve conflicts using external tool (Filemerge/opendiff)

I'm having problems getting SourceTree to launch Filemerge from either of the two menu options.

I see the "visual merge" dialogue box appear, and BACKUP, BASE and REMOTE files appear in the working tree. Then after about 5 seconds the dialogue box closes itself, but Filemerge doesn't launch.

Clicking the "External diff" button at top right does launch Filemerge - with 'null - /dev' in the left-hand pane, and the conflicted file in the right.

My Xcode path is /Applications/ Running opendiff at the command line works with no problem.

I've tried setting the preferences settings as both 'FileMerge' (with no diff command, and empty arguments) and as 'Other' with the diff command as 'opendiff' and arguments as $LOCAL $REMOTE -merge $MERGED (as per

(Edited to add: this is the content of my global .gitconfig:


tool = default-difftool

[difftool "sourcetree"]

cmd = opendiff \"$LOCAL\" \"$REMOTE\"

path =

[mergetool "sourcetree"]

cmd = /Applications/ \"$LOCAL\" \"$REMOTE\" -ancestor \"$BASE\" -merge \$

trustExitCode = true

Does anyone have any ideas?


7 answers

I am seeing the exact same issue, but my external diff/merge tool is Araxis Merge. Everything was working fine through multiple individual 3-way merges. Then, without any reason I can see, Sourcetree started acting as described above. It creates the merge files in the folder, a dialog flashes up (but goes away too quickly to read) and nothing else happens.

Does anyone have an aswer for this? It is very frustrating.

I am seeing this issue as well as Bennett Smith. Even changing the tool back to default / non-external tool does not have any effect. Help!!!

BTW, I am using Windows version, and use beyond compare as external diff tool. The suggested link above does not help.

Same problem as described above with tortoisemerge and with kdiff3


I get the same problem with opendiff on mac osx 10.10. Command line works fine. Source tree does not. Please fix!


Also note that sourcetree creates backup files upon clicking "launch external merge tool", but does not launch the merge tool!

I noticed that SourceTree will hang if one of the files to diff had been removed. I submitted a bug regarding this. Check to see if this is your case.

The fix is yet to arrove but there's a workaround at

Suggest an answer

Log in or Sign up to answer
Community showcase
Published Oct 23, 2018 in Sourcetree

Tip from the team: configure your repos for hosting goodness!

Supported Platforms macOS Windows We recently introduced support for additional hosting services such as GitHub Enterprise, GitLab (Cloud, Community Edition, Enterprise Edition), and...

1,110 views 4 2
Read article

Atlassian User Groups

Connect with like-minded Atlassian users at free events near you!

Find a group

Connect with like-minded Atlassian users at free events near you!

Find my local user group

Unfortunately there are no AUG chapters near you at the moment.

Start an AUG

You're one step closer to meeting fellow Atlassian users at your local meet up. Learn more about AUGs

Groups near you