I opened the file with a hex editor and it contains zeros only. So unlike my map accidentially encoded to 8 million zeros, everything's gone.

however, i cant believe things like this happen.

Hello,

somehow my save got invalid, i cannot open it anymore, neither with factorio nor with any zip-tool or zip-repair-tool.

It propably happened when i started factorio. It didn't load completely, even after 2 minutes. I canceled the task (notice that factorio didn't even open my game).
After ...