Event ID 1530 -Avira Antivirus

In Event Viewer is the following error Event ID 1530:
Windows detected your registry file is still in use by other applications or services. The file will be unloaded now. The applications or services that hold your registry file may not function properly afterwards.
DETAIL -
1 user registry handles leaked from \Registry\User\S-1-5-   _Classes:
Process 1788 (\Device\HarddiskVolume1\Program Files (x86)\Avira\AntiVir Desktop\avguard.exe) has opened key \REGISTRY\USER\S-1-5-21-1856070677-1184215578-1670999655-1001_CLASSES\SOFTWARE\Microsoft\Windows\CurrentVersion
Source
They suggest to uninstall Sandboxie and check whether error will still happen, and it still does after Sandboxie is completely removed. Always on shutdown, always event 1530.
After playing with Avira settings, I found out that disabling option "protect files and registry entries from manipulation" stops event 1530, with or without Sandboxie installed.