I can't degrag my registry anymore, because acces to registry entries is denied. I just wonder is Avast now blocking attempts to rewrite registry entries? This problem started after installing Avast 2015. I have been able to defrag before. I have tried stopping Avast services, but that didn't help.
I found this answer on some registry defrag site regarding to errors. (not the same app i'm using though):
Most likely, you are getting this error because Registry Defrag is conflicting with your anti-virus. Some anti-viruses (we know about BitDefender and Auslogics Antivirus) block all attempts to rewrite registry entries, which doesn’t let Registry Defrag do its job. If that’s the case, then the only solution is to uninstall your antivirus.