ClamWin And ClamWin Portable Updating Is Broken:
As of February/March 2021 updating the virus definition ("signature", "database") files isn't possible from inside of ClamWin/ClamWin Portable. You'll instead have to use a workaround by manually downloading them in a web browser, and the web browser will have to be a modern current version. Note that downloading in old out-of-date web browsers such as on old unsupported Windows operating systems <em>(which also have to use old web browsers)</em> will always fail, and updating will also fail if using a download manager.
There Are Multiple Reasons This:
· ClamAV has ceased support of versions older than 0.100.0. Both ClamWin/ClamWin Portable are at version 0.99.4 which was released in 2018 so they’re both three years out-of-date, and also over six versions behind ClamAV.
· https://database.clamav.net has updated the site security and now uses Cloudfare to protect the site, which in turn means ClamWin/ClamWin Portable can’t download updates anymore, and currently only modern current versions of web browsers are capable of downloading from the site.