Hi Avast,
Since updating to program version 5.1.889 of Avast, accessing .exe files accross the network causes the computer to lock up and the only way of recovering is through a hard reset.
As we are a reseller of Avast we have many clients using Avast and so far have run into 4 identical situations like this where we have had to uninstall 5.1.889 and install an older version. We expect to run into many more as clients update to the newer version of the programs.
The pattern that is appearing is that this is affecting win7 machines (both 32 and 64 bit) that are accessing .exe files across the network. If you do not access any network .exe files then you can use the PC without a problem, but as soon as you do it freezes. There don’t appear to be any event viewer messages that refer to these freezes.
UPDATE
This has now also happened on an XP Pro SP3 machine. Only difference is instead of freezing the computer almost instantly, it slows it down dramatically initially, and then eventually freezes.