I just found the system drive were filled with unpxxxxxx.mdmp under c:\ProgramData\AVAST Software\Avast\log
Ran ccleaner removed them. and it’s appearing again this morning and it’s accumulating.
There has been no popups, or alert saying anything might be wrong.
Avast Software may want a sample of those files.
Upload a few of those to ftp://ftp.avast.com/incoming/
file uploaded
Okay. I sent a PM to one Avast developer to look at those. Now we have to wait.
is there a solution yet? 
I find the some what avast module crashed and generate these dump file, at the same time my Internet connection will become time out.
I’ll have to restart Widnows to solve the problem.
At the moment I’ve disable all network related protection and leave only file protection & behaviour protection. It seems to reduce the dump file / crashes