Sophos On Access Scanner disabled due to missing pattern files

Question

Hi, 
 
 i have a lot of mac systems with catalina and an Enterprise Console with V5.5.1. Some of the macs cannot start the on access scanner after a fresh install of Sophos Anti-Virus for Mac. 
 
 In the About Sophos Anti-Virus window there is no Thread Detection Engin and no Thread Data. Both points just show (null). 
 
 Did anyone experience a similiar problem already and found a solution. I havent found anything via google or in this forums. 
 
 Thank you, Stefan

Stefan Beier · Accepted Answer

I think i figured it out by myself. In some strange circumstances (seems to be catalina 10.15.3 only), you need to allow 3rd party apps (in this case particulary apps from sophos) in the security dialog in the common pane additionally to the full disk access. Otherwise sophos wont be able to read its own patternfile versions. I had three different macs with this issue, even after reinstallation of sophos. 
 
 Thank you, Stefan