Problem

Pushing to a git repository that has been configured as a mirror does not work, reporting an error like this:

error: --mirror and --tags are incompatible

Cause

You created the remote outside of SourceTree with the --mirror=push option. This forces git to add --mirror to the command line which is incompatible with some more specific options, such as --tags, which SourceTree uses to push tags by default.

Workaround

The --mirror=push remote configuration is really a convenience for the command-line so you don't have to type as much; since SourceTree is more specific about how to push this is going to conflict. Unfortunately git provides no way to override the forced --mirror option so effectively this remote is not usable with SourceTree. Please create another remote pointing to the same location without the forced --mirror option (for example, create it inside SourceTree), or remove this option from the remote in your .git/config .

You should not need the --mirror option with SourceTree anyway since it defaults to selecting your tracked branches in the push dialog, and reducing typing is not an issue.