The exclusions suggestions have been asked many times and Alwil team have responded the same, they won’t add it as it is too easy to click it accidentally letting a malicious file through the net.
Their decision is that exclusion should be a deliberate act and not a single click option, this is to ensure the ‘majority’ of users are protected against accidental exclusion of malware.
The correct way to deal with false positives is by confirming and reporting them (see below) so that they can be analysed and the VPS corrected, this benefits all users.
There is a new reporting of FPs function under development, a link to report the detection as an FP in the alert window (in the beta 4.8.1256 build being tested). This however, won’t add to exclusions lists, you still have to choose an action.
You can delay the update manually:
You need to edit (using notepad) the [InetWD] section of the C:\Program Files\Alwil Software\Avast4\Data\avast4.ini file and add the following line (depending on your connection type enter one or other of the Bold lines below):
Dial-up connections, add this line: RASWaitSeconds=120
Broadband connections, add this line: AlwaysConnectedWaitSeconds=120
[InetWD]
AlwaysConnectedWaitSeconds=120
Or
RASWaitSeconds=120
When complete save the changes, avast’s self-defence module will ask for confirmation, etc. answer Yes.
The figure is seconds and the above equates to two minutes, you could try that and adjust upwards if required, 180, 240, etc.
You could also check the offending/suspect file at: VirusTotal - Multi engine on-line virus scanner and report the findings here. You can’t do this with the file securely in the chest, you need to extract it to a temporary (not original) location first, see below.
Create a folder called Suspect in the C:\ drive, e.g. C:\Suspect. Now exclude that folder in the Standard Shield, Customize, Advanced, Add, type (or copy and paste) C:\Suspect* That will stop the standard shield scanning any file you put in that folder. You should now be able to export any file in the chest to this folder and upload it to VirusTotal without avast alerting.
If it is indeed a false positive, see http://forum.avast.com/index.php?topic=34950.msg293451#msg293451, how to report it to avast! and what to do to exclude them until the problem is corrected.