Are you able to [build Git](https://github.com/git-for-windows/git/wiki/Building-Git)? It would be interesting to instrument the code (read: litter it with debug print statements) and figure out _where_ the actual root cause lies, and what error code is actually returned (and why). For starters, I would start with these code locations, if I were you:

[zorro-ryp]

Are you able to build Git? It would be interesting to instrument the code (read: litter it with debug print statements) and figure out where the actual root cause lies, and what error code is actually returned (and why). For starters, I would start with these code locations, if I were you:

$ git grep "unable to resolve reference" \*.c
refs/files-backend.c:                           strbuf_addf(err, "unable to resolve reference '%s'",
refs/files-backend.c:                           strbuf_addf(err, "unable to resolve reference '%s'",
refs/files-backend.c:                           strbuf_addf(err, "unable to resolve reference '%s'",
refs/files-backend.c:                   strbuf_addf(err, "unable to resolve reference '%s': "
refs/files-backend.c:                   strbuf_addf(err, "unable to resolve reference '%s': %s",
refs/files-backend.c:                   strbuf_addf(err, "unable to resolve reference '%s': %s",

Originally posted by @dscho in git-for-windows/git#2778 (comment)