Yes, if a solution has been found, please post it.
I imagine that Avast are putting the finishing touches on a new public release. Vlk had me test an unfinished build yesterday, and it does seem to have corrected the major problems.
In the meantime, you might try the following workaround:
1. Turn off Avast self-defense.
2. Disable auto-updates. Alternatively, set the auto-update interval to a much longer period than the default 120 minutes. For example, if you set the auto-update interval to 1440, an auto-update will take place once per day, and the Exchange crashes will occur at most once per day. In any case, you can still perform manual updates at any time without crashing Exchange.
3. Restart the avast! Antivirus service.
4. If Avast crashes while the service is being restarted (a problem corrected with the test build), restart the server.
5. Turn on Avast self-defense.
kwg