That certainly isn’t normal, I certainly haven’t experienced that in the past whilst installing a program, but I’m not running the current beta build on any of these systems. I have avast free on three systems, XP with two hard drives and multiple partitions, win7 32bit netbook with only one drive and two partitions and a win10 64bit with 1 SSD drive and 1 HDD drive (neither are partitioned).

That said I’m not running the current beta on any of these systems, so I can’t say if this a beta related bug.

Did you do a clean install of this beta or update from the program interface ?
You may want to consider restoring factory defaults in the Troubleshooting section of the UI, in case any of your settings are aggressive.