I manually enabled all packers in the enchanced UI

Not a good idea. I generally strongly recommend against such a setting. The thing is, even on a clean Windows installation, you’ll be seeing huge delays when Windows e.g. touches its C:\Windows\Driver Cache\i386 folder (the file driver.cab located in this folder contains thousands of files, and its decompression takes a LONG time). The same applies to the contents of the C:\Windows\Installer folder. And trust me, Windows touches these very folders quite often.

So, my recommendation is to stick with the defaults (as far as the Packer settings for the on-access scanner go)…

Cheers
Vlk