Project deletes after trying to download archive

Originally from https://github.com/gitlabhq/gitlabhq/issues/9168

When I click on "Download zip" (or other formats - it doesn't metter), I receive error with 500 status. On server, ALL my projects folders become deleted. In interface then I see "No repository" error. First time I've found this error on 7.7 version. I've tried to find out the reason in logs, but haven't found anything helpful.

I'm using now gitlab 8.5.4 and bug still exist. Everytime I upgrade gitlab, I'm looking through sources and comment buttons allowing to download project.

I thought, that it was caused by symlink to projects folder (as I know gitlab doesn't support it). But when I refused from using symlink, the only change was, that I've start receiving zip-file with my project. But ALL my repositories are still dropping.

If you haven't time to explore this issue, it would be great if there will be an option disabling download project function.