Sorry, but replacing software WITHOUT ANY WARNING OR ANNOUNCEMENT (that v4.8 will be replaced) is NOT SMART, IT'S SABOTAGE!!!
The result is data loss and the need to reinstall some special tools that avast is unable to not delete in standard settings that are automatically set with the new version. The first thing that new avast did was deleting some daily or weekly used tools - again WITHOUT ANY WARNING, as it is not installed in the way and the settings the former version was, but with settings to delete without warning!
DELETING WITHOUT WARNING (as set in standard stettings) again is AN ABSOLUTE NO GO!