The IM is an internal avast forum function, which is restricted to avast users that have at least 20 posts. So there is a very limited chance that a spammer will get to 20 posts to be able to use it internally.
I just use my other computer which is my other house.
It continues BUT! i noticed that when reaching 19.6mb, Avast will scan deeply which stop my download for about 5seconds then the download continue. I observe this on my other home computer.
I dont know what is the cause because i have avast with the same version.
I think its not a malware because if that case avast will block it! But No!
Avast will make my downloads finish but its incomplete without any warning.
Btw. The one that i download yesterday installer, I install it and scan with Avast and MBAM all clean.
I went to the site and downloaded the full client, first with Firefox 7.0.1 and then with GetRight download manager. Both downloads were the same size and at approximately the same download speed. They were not 643 MB. Perhaps I downloaded a different file. ???
DFI_SFSingapore_150911.exe
Size: 629120599 bytes
Modified: Sunday, October 30, 2011, 11:38:17 AM
MD5: C946B378CE68FC35EF74E6B0ADA6AF4A
SHA1: A19D3D8255BA2CBC44A675285595B615AC95B3EC
CRC32: 5F3208DD
Like you, in Firefox the download paused slightly while Avast scanned the partial download at 19.4 MB for me, then proceeded to completion. With GetRight, although I did see some Avast activity during download much sooner there was no delay in download. I have GetRight set to use AshQuick.exe to scan the download upon completion.