Hi,
On my Windows 8.1 I had to deactivate Microsoft Family safety (http://windows.microsoft.com/en-us/windows-8/family-safety) because Avast prevented my daughter’s account to use Google (on Chrome, Firefox, …). And it also, during some days, crash my Windows 8.0…
I seems linked with the HTTPs (deep) analysis with Avast…
Cf a thread to Microsoft, sorry it’s in French:
http://answers.microsoft.com/fr-fr/windows/forum/windows8_1-security/le-contrôle-parental-bloque-le-moteur-de/b82b97e7-7619-4147-860f-55f4393f968c?msgId=28a53c16-6dfc-4e61-a583-487f661c130b
Regards,
Pascal