More data points. I have reproduced the problem on $ git --version git version 1.8.5.2 (Apple Git-48) $ python --version Python 2.7.5 $ uname -a Darwin Kernel Version 13.3.0: Tue Jun 3 21:27:35 PDT 2014; root:xnu-2422.110.17~1/RELEASE_X86_64 x86_64 However, it the command is used on a new empty repository, there is no failure. Running a second time causes the failure. Thanks for any help you can offer in tracking down this problem! -- View this message in context: http://git.661346.n2.nabble.com/git-p4-diff-tree-ambiguous-argument-error-tp7614774p7614882.html Sent from the git mailing list archive at Nabble.com. -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html