Many legitimate installers end in -win64.exe (e.g., darktable-win64.exe or vlc-win64.exe ), which are simply 64-bit installers for those specific programs. However, a standalone file named exactly wind64.exe or win64.exe in a startup folder is almost certainly malicious. Recommendation If you find this file on your system, you should:

Right-click the file → → Digital Signatures tab: