4.20 prev1 - bitdefender reports virus in exe

Trying to install 4.20. After a long while installing it fails with error IS MF01-5-5.
Tried the suggestions in the knowledge base (install on another disk, mem check, re-installed the launcher). Doesn’t work.

Just had a look at Bitdefender. A virus in the installation file? System is clean so maybe a virus in the installation file?

Edit; did some Google-ing. Turns out happens more often with virus scanners. After adding the UE path to Bitdefenders whitelist it installs fine