A customer, understandably panicked, contacted us to report that after installing the latest update, when he ran Gig Performer he just got an empty rackspace. Also, Gig Performer started a complete scan of his VST and AudioUnit plugins as if they had never been seen before. It was as if the update turned into a completely fresh install.

Plugin Scanner Gig Performer

After some investigation, we discovered that after the update completed, the customer was prompted to remove the update installer which he did. It turns out that this prompt was coming from a program called Clean My Mac 3 which, among other things, monitors installations and offers to remove unnecessary files. However, as far as we can tell, Clean My Mac 3 decided that the support files in ~/Library/Application Support/GigPerformer and all files ending in .gig  were unnecessary and it deleted them.

Removal of the former would cause Gig Performer to rescan all plugins and removal of the latter would of course result in existing gig files not being found, leading to a brand new empty rackspace appearing.

We have reached out to the developers of Clean My Mac but we would encourage you to be very careful about using programs that can modify or remove files without your approval or even with your approval if you just accept the recommendations as to what to delete.

While rescanning plugins unnecessarily is just a nuisance, loss of gig files is clearly a huge problem so make sure you create backups of your gig files somewhere where they cannot just be blindly deleted by mistake.
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Further reading:
Troubleshooting (User Manual)
Tips to troubleshoot your computer based setup (blog)