I'm having a similar problem as of today... I use an older version of Avast! and as of 17:20PM today I've had the Avast! Antivirus Service unexpectedly stop and restart itself again. (In the Windows Resource Monitor the Avastsvc.exe process disappears and then reappears about 5 seconds later)
Everything on startup is fine... this seems to happen at random intervals and has happened 4 times today according to my windows logs with the same error code.
Log Name: System
Source: Service Control Manager
Date: 19/08/2016 17:20:40
Event ID: 7031
Task Category: None
Level: Error
Keywords: Classic
User: N/A
Computer: MikeStevens-PC
Description:
The Avast Antivirus service terminated unexpectedly. It has done this 1 time(s). The following corrective action will be taken in 5000 milliseconds: Restart the service.
Event Xml:
<Event xmlns="
http://schemas.microsoft.com/win/2004/08/events/event">
<System>
<Provider Name="Service Control Manager" Guid="{555908d1-a6d7-4695-8e1e-26931d2012f4}" EventSourceName="Service Control Manager" />
<EventID Qualifiers="49152">7031</EventID>
<Version>0</Version>
<Level>2</Level>
<Task>0</Task>
<Opcode>0</Opcode>
<Keywords>0x8080000000000000</Keywords>
<TimeCreated SystemTime="2016-08-19T16:20:40.748470000Z" />
<EventRecordID>935387</EventRecordID>
<Correlation />
<Execution ProcessID="680" ThreadID="3632" />
<Channel>System</Channel>
<Computer>MikeStevens-PC</Computer>
<Security />
</System>
<EventData>
<Data Name="param1">Avast Antivirus</Data>
<Data Name="param2">1</Data>
<Data Name="param3">5000</Data>
<Data Name="param4">1</Data>
<Data Name="param5">Restart the service</Data>
</EventData>
</Event>
Not sure what caused this... I've never seen the service die before...ever.