..
Yeah... is the price of the improvement..
indeed a painful improvement for too many out there ending up in a clean-wipe to make 4.8 work 
not exactly a perfect migration, no? 
Lets face it we are spoilt with the avast incremental updates, which have served me well for the 4 years I have been using it and no problems updating to 4.8. I even went through the beta trial, which on most programs require that you uninstall the beta before installing the regular version.
I have numerous applications that any program update requires a re-installation or it falls over. So we have gotten used to the incremental update working, so when it fails it is a big issue.
He**, a JAVA update requires totally uninstall previous versions and install the latest update as there is zero update process, what an absolute waste of bandwidth and a right royal pain in the a** on dial-up.