Yep, that?s almost certainly the problem ? plusifier.exe is part of the JJ2+ installer and sometimes antivirus software falsely flags it.

Try this:
1. Go into your antivirus
2. Restore or whitelist plusifier.exe.
3. You might also want to add the whole JJ2+ folder to your antivirus exceptions.
4. Then run the installer again.

Happened to me before too, should work after that 👍