Fixing Trac Warning: Can't synchronize with the repository (No changeset X in the repository).

When you get the trac error Can't synchronize with the repository with the specific reason that it does not have a specific changeset in the repository, en error such as below, the fix may be an easy command.

Warning: Can't synchronize with the repository (No changeset 44ac558946c26785987f0e500d23137d36bc537e in the repository). Look in the Trac log for more information.

(The ridiculously long changeset number is a hash, which is how Git makes distributed version control possible.)

Resolution

On the server which hosts your Trac installation, run the command trac-admin /path/to/trac/project resync.

Might look something like this.

ben@server:~$ sudo trac-admin /srv/trac/projectname resync
[sudo] password for ben:
Resyncing repository history...
368 revisions cached.d98bd47b5262c3924ba31]
Done.