osx - SourceTree filemerge quits immediately and creates 4 files. How to fix it? -

yesterday merge files in sourcetree external tool filemerge. today, sourcetree wanted me register me, , after successful registration, couldnt start filemerge.

when choose "launch external diff tool" contextmenu of file, 4 files appear (backup, base, local , remote) filemerge quits immediately.

when launch external diff, filemerge displays in left /dev/null source. how can fix it? in preferences choose filemerge external diff tool. have write diff command source tree manually, give right local version of file? how can it?

thanks

i solved problem.

if have merge conflict file doesnt exist in 1 of branches, filemerge quits immediately.