Thanks,
Yet , this is exactly what I did
1-un-installed v2218 , I returned to this release for security reasons (WS out with v2233)
2-used the appropriate removal tools in Safe Mode
3-installed AIS beta 2016 in normal mode => but avast doesn't want my avastlic file in progress (until october 2016)
Anyway , the main will I have installing beta was to enable Web Shield , and licence or not licence ,this shield turns off immediately after I manually active.
Other big trouble , the special & appropriate removal tool for beta didn't work when I ran it in SM (just 1/2 second to see avast location folder , then tool UI closed)
nb:others removal tools (for v2233 or v2218) work fine anyway
Now , after a long time spent trying to repair the damage , I hope it will not stay too annoying traces of installing the beta.
Apparently, everything is returned OK with the 2218 release.
I also hope avast support has not forgotten me and my package sent there are 10 days.