I experienced the same behavior and it could be related to a couple of things. First, only referenced files are mirrored (e.g. a page links to them). Try adding a link to a file on a page, publish the page, and then run the mirroring job. If this doesn’t do it, it could also be related to a licensing issue. If either site has an invalid license you may experience intermittent issues. If so, try resetting IIS on the destination as the cache may not have been updated because of the license issue.
I hop this helps,
Joe is right, the mirroring will only add files in use
Some findings can you read about here
Mirroring 2.0 in CMS 6 doesn't seem to mirror any files . I've setup two fresh public template sites . Mirroring suceesfully mirror all pages but doesnt move any image / file into VPP.
There is no error in log files and mirroring montoring also shows that 'Files mirrored'.
Any idea . Am I missing something very basic ???