I noticed this problem since some time, but I hoped it would get fixed in an update. If I enable "Scan secured connections" under the Web Shield advanced settings, Dropbox refuses to connect. Since the beta I read that it needs to be added to the exclusions list, which didn't work. Then I read that avast will have a "whitelist" in the stable release, and even though "client.dropbox.com" has been automatically added to the exclusions list, with the https service, it still refuses to connect. Is there anything I can do to fix this?
Well I had this problem too, I did that and it didn't work... then I see 3 options (whit check blank), the last one said "analyze protected connections" and unchecked it... It fix all my problem... (leaving the dropbox server of course!)
Apologies for my english, I actually speak spanish