Avast Home upgrade to 4.8 'freezes' machine high CPU

Client with Avast Home free has been updated overnight with 4.8. System apparently ‘stalled’ since this. When I visited to determine problem found avast-setup running at 85-95% CPU.
Reboot (hard power-off as system wouldnt respond), and on reboot similar problem occurs.
Eventually uninstalled Avast 4.8, reverted to 4.7, and all is OK.
Is this a known problem, please?
Thanks
Ray

What else is running? Applications, processesses (also the ones in te background)

Nothing at the stage of the ‘problem’, cause any startup program cannot get CPU allocated to it. Avast-setup is madly consuming all available cycles.
Managed to, eventually, start the system - took nearly 35 mins before I could get to the system to get the task manager.
One main task was Yahoo Messenger (dont ask). Removing this from the startup group did not solve the problem. Only other specific tasks are ctfmon, and Toshiba power-saver modules. Relatively clean machine; no malware, bots, etc.
Removing 4.8, as earlier, and reinstalling 4.7, the system worked fine.
Ive since reinstalled 4.8 from the full instal package, with the same symptoms.

It would be useful to get a memory dump of the offending process (Avast.setup), or the whole system at the moment the problem is simulated.

So you’re saying that it takes ages to do anything on the machine, right? (it’s probably a single-core / no-hyperthreading CPU, isn’t it?). In this case, it may be simpler to do the full system dump.

The procedure of creating the dump (and delivering it to us) is described e.g. here: http://support.avast.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=71

Thanks
Vlk

I encounter exactly the same problem on my laptop ASUS F2HF series with Celeron-M440, 1024MB memory and my PC Athlon 2500, 2048MB memory…When I shut down avast 4.8 everything comes to normal…
I have run a full system check and cleaning along with defrag of the drives…just regular staff…and it still keeps coming back…

Please do as Vlk asked