External Diff button does nothing

[Frode Nilsen]

External Diff has stopped working for me. It used to work and I don't know when it stopped working. Beyond Compare was what I used, but I've tried all other options including setting "CMD" as custom external diff, just to see a console window open. It does not.

I'm running Windows 7. Beyond Compare is installed in the default location and is working as expected when I run it outside SourceTree. I've tried diff'ing both on git repos and mercurial repos.

Is there something I do wrong? Any tips on how I can fix/debug this issue?

Pastebin of my sourcetree.exe.config : http://pastebin.com/sFpba1A6..or at least I think it is. Weird thing is that the timestamp on the config was from April this year, and "DiffTool" is -1 (system default from what I've read), although I've set it to Beyond Compare... Might Source Tree store the config elsewhere? There's a fucked up corporate home drive sync setting here that might interfere.

[Frode Nilsen · Accepted solution]

This suddenly started working again. I don't know what I did.

[Balázs Szakmáry]

The answer here might help.

[Seth]

There is an option in SourceTree that controls whether it is allowed to modify the git config file. That should be allowed if you want to set the diff tool with the SourceTree options dialog.

[Frode Nilsen]

It is and was set to true