This post is made due to CCleaner's fault of deleting some of the registry entries. In my case - it is simply one.
Some of helpers before told me it is associated with an Avira Free edition anti-virus. Here it is...
__________
Unused File Extension
{80b8c23c-16e0-4cd8-bbc3-cecec9a78b79}
HKCR\{80b8c23c-16e0-4cd8-bbc3-cecec9a78b79}
__________
It is exactly what CCleaner alerts.
Thanks in advance!
-Peter
P.S. From my experience, I know that one registry keys are related to others. Might be I need a deep registry scan by some other software to identify what other registry entries are related to this specific key to batch remove it, or keep.
This is by design of the antimalware program, it hides its registry entry so that programs can't remove easily. Not everything listed in ccleaner's (or any registry "cleaner") should be removed. Please take some time to read my signature and its advice on registry cleaning