I tested downloading MS-DOS viruses from http://vx.org.ua/ to test if Avast detects any of these.
It didn’t detect any of the ones I had downloaded. But I downloaded an old version of F-PROT for MS-DOS and it found the viruses I had downloaded.
Please fix this, because in my opinion Avast should also be able to detect old viruses.
Most Dos virus only exist in collections (like the old vx collection) …they are not out in the wild, and most dont work on new OS
Why? Are you running any old MS-DOS systems?
No? Do you know anyone who is?
I know I don’t want my system running more slowly (or detecting more false positives) because Avast is checking for viruses that can’t possibly infect it.
-Noel
Actually I’m still occasinally using MS-DOS and also download different old programs several times a week, so I would like to be sure that they also clean. If Avast is not going to make any improvements to this, then I have to test if some other modern antivirus will work better.
No modern av will detect them.
There is no need for it anymore.
modern AV that does not support old OS will most likely not detect virus that dont work on new OS
all AV vendors know about the VX site, if they need any samples from there they would go an pic
all those samples at VX have also been scanned at Virustotal, so all AV vendors listed at VT have already seen those samples
so you test those samples at VT and see who still detect and how old they are 
First submission 2008-09-12 23:46:32 UTC ( 6 years, 1 month ago )
https://www.virustotal.com/nb/file/8d8436053ab3a1a4753cf45a7f8dc76feae059db78d02cbd757570afde7c9e53/analysis/
First submission 2006-08-06 03:32:08 UTC ( 8 years, 3 months ago )
https://www.virustotal.com/en/file/fd610152696dd0c0fa53f7c5c630adee910005e9cf07027ecb6023304a72cfd8/analysis/
old AV that still support old OS will most likely detect
AV = AntiVirus program
OS = Operating System (win 3.11 / win95 / win98 / winXP … )
ClamWin is a Free Antivirus program for Microsoft Windows 8/ 7 / Vista / XP / Me / 2000 / 98 and Windows Server 2012, 2008 and 2003.
you need to install Clam Sentinel to get realtime protection
But if people still using them and willing to pay for protection, then why not?Why wasting time, money, resources just for a handful of people? If people are willing to pay for it... Hmm I guess they will have to pay around $10.000 or something per license to make the developers break even.
Avast! has moved alot of these detections to the cloud.So Avast will detect them when executed by filerep or deepscreen.But again detecting these old baddies is useless most of them are not existant right now.
I tested today with other settings in Avast, but it didn’t find anything at all.
F-Secure found old viruses with basic settings, so I have to consider moving to it.
Quite a statement…again. Bitdefender does detect them.
I can confirm we removed the detection of most “extinct” viruses, including those for MS-DOS, starting Avast 2014. This helped us save a few tens of megabytes of RAM usage.
There’s no immediate plans to change that.
How about adding an option to Avast settings for these? To save RAM usage, it could be disabled by default, but if users wanting more protection, then it could be enabled.
There are many ways to handle this, but I don’t think this should be removed totally.
I think it’s not that simple. We’re not talking about disk usage, but the final engine and Avast performance: new technology that requires to extinct older ones.
Whats the point of detecting something extinct?? When if you do run then on today’s MS supported OS like Win7/Win8 those guys wouldnt run on them or they would run and then be unable to do anything and crash.
Those MS-DOS stuff are dinosaurs in the malware age.What’s the point of wasting time and energy on detecting something that is not going to be alive in the real-world for not more than a day or less or which is years old like MS-DOS viruses.