I recently discovered that Avast was flagging my Windows installer as malware. Looking into it, it seems that it didn't like the file "uninstall.exe", which is included by the NSIS installer. I tried repackaging the game using the exact same files, and this time it doesn't flag anything. It seems like their malware detection program is very buggy. Anyway I discovered a site where you can check your installer before uploading it: https://www.virustotal.com/gui/home/upload .