Stevo

Hello @Vistapocalypse, I am still running Avast Free 18.8 and also Defender. I edited registry as per Avast Forum (I know it was Avast 12.2.2276 & W7 but gave it a try) and runs OK. Yes, I did also install the last-ever Server 2008 updates on Windows Vista and have not observed any issues. Just for my curiosity, why have you chosen not to update to build 6003 + sha2 support ?

Yes. I updated my WD definitions to 1.307.2582.0 yesterday 18/01/2020 using manual download/update. (Using WD 'check for updates' before the manual download/update told me that I was up to date with no new definition updates)

Success finally. All updates installed and Avast 18.8 running OK now. @Vistapocalypse. Thanks for your link to spiceworks. I was following that thread too and the persistence of @spicehead-3vg61 grabbed the attention of @Peter (Avast) mentioning my original post here at MSFN. The first Avast/AVG micro-update (released in April) did indeed change my registry settings for Csrss as @artomberus showed in his screen shot (but in my case using Avast instead of AVG) but my system was still BSOD on reboot. Avast was showing:- Avast program version 18.8.2356 (build 18.8.4084.0) Virus definitions version 190521-4 After confirmation from @Peter (Avast) on 4th June, I ran the Avast Emergency Updater: (just to be sure) (at this stage I had not seen a difference in the ‘About Avast info’) C:\Program Files\AVAST Software\Avast\AvEmUpdate.exe as detailed here. After a reboot: Avast now showing:- Avast program version 18.8.2356 (build 18.8.4084.0) Virus definitions version 190606-4 It appears that Avast Free (For Home) did not update to program version 19.3 (and later to 19.5) as indicated here for (Avast Business Antivirus) but remains at 18.8, BUT now the second micro-update (within the Virus definition update) (released on 4th June) has resolved the BSOD and I am now up to date with MS Updates...Phew! 

Success finally. All updates installed and Avast 18.8 running OK now. @Vistapocalypse. Thanks for your link to spiceworks. I was following that thread too and the persistence of @spicehead-3vg61 grabbed the attention of @Peter (Avast) mentioning my original post here at MSFN. The first Avast/AVG micro-update (released in April) did indeed change my registry settings for Csrss as @artomberus showed in his screen shot (but in my case using Avast instead of AVG) but my system was still BSOD on reboot. Avast was showing:- Avast program version 18.8.2356 (build 18.8.4084.0) Virus definitions version 190521-4 After confirmation from @Peter (Avast) on 4th June, I ran the Avast Emergency Updater: (just to be sure) (at this stage I had not seen a difference in the ‘About Avast info’) C:\Program Files\AVAST Software\Avast\AvEmUpdate.exe as detailed here. After a reboot: Avast now showing:- Avast program version 18.8.2356 (build 18.8.4084.0) Virus definitions version 190606-4 It appears that Avast Free (For Home) did not update to program version 19.3 (and later to 19.5) as indicated here for (Avast Business Antivirus) but remains at 18.8, BUT now the second micro-update (within the Virus definition update) (released on 4th June) has resolved the BSOD and I am now up to date with MS Updates...Phew!