I have installed Avast 4.6 and the ISA 2004 plug-in on 3 win 2003 Sp1 servers. If I enable the virus scanning, users complain that their downloads are downloading corrupted. It is not a specific site, update.microsoft.com, hp.com (print drivers) as examples consistently fail.
Any Ideas?
Steve,
I also was being plagued with download corruption from multiple sites. This solution worked for me:
http://forum.avast.com/index.php?topic=15653.0
By the way, the corruption returned sometime later. I think that I had run the Avast repair feature, which probably overwrote the new .dll file with the original one. Installing the new .dll file once again corrected the problem.
Ken
Right. BTW the fix will be included in the next program update, due in about a week.
Thx Vlk
Thank you for the update, however, i installed this fix yesterday. interestingly enough, the version of the one I replaced was the same, it did not have any effect on the corruption.
Steve,
If you are downloading a file that had been downloaded previously and corrupted, you might be retrieving the corrupted file from the ISA cache. As an experiment, you could temporarily turn off HTTP caching in ISA. If caching seems to be the cause of the continued corruption, you would then need to clear the ISA cache.
Ken
Great thought! Let me try that.
Clearing the cache on the ISA servers worked, the downloads are working fine so far.
Please note that the next reboot of the server will cause the patched file to be replaced by the original (buggy) version. That is, if you restart the server you’ll need to replace the file again.
Of course, this is only the case till the update gets official (again, I expect this to happen during the next week).
Thanks
Vlk
So if the new version is coming out soon, and I have to make a recommendation next week on an antivirus solution in our enterprise environment, whom do I take to lunch to get a beta version now, for testing?
You can take ME to the lunch 
As a matter of fact, I’m in the US (in Redmond) during the next week…
Anyway, I can certainly give you a beta that should have this problem solved.
Please send me an email and I’ll send you a download link.
Thanks
Vlk
Won’t you betrayal us to Microsoft, will you? ;D