External Merge tools won't launch

[Peter Staab]

I'm using SourceTree 2.0.5.2 on OSX 10.10 and have the latest Xcode and command line tools installed.  When trying to do a merge and get conflicts, when launching the external merge tool, I get the window warning to quit the merge tool, then it disappears and nothing happens.  Is there a place that an error would be logged? 

I'm using FileMerge as the default.  I can open it up via spotlight no problem. This used to work a couple of months ago.  

[Brandon Owensby]

I was researching a similar issue with Windows and Beyond Compare.  After playing with it all morning I learned that no matter which merge I picked in source tree except System Default it didn't work.  I then put it back to System Default and configured git to use the merge tool of my choice and this worked perfectly.  I hope this helps.