Thread:Project:Support desk/File upload not possible: MIME Type or wrong ZIP detection/reply

You might want to try playing around with Manual:$wgCheckFileExtensions Manual:$wgStrictFileExtensions Manual:$wgVerifyMimeType. In the past I've had similar problems with the automatic MIME detection and checker, and I've been able to resolve them with these. However, if you are concerned about actually scanning them for security reasons, it may be worth reporting this as a bug. I would recommend testing it with other completely different files to verify it's a problem first.