Hi lakerb,

Such situation could be theoretically caused by updated AVG removing infected items. However, the same items should have been detected by AVG after it is updated again. If that wasn't the case, the cause of the issue is quite unclear.

Should you suspect the system could be infected, please provide us with AVG full computer scan result export and msinfo output. Should the issue occur again, please provide us with all AVG log files and system event logs too, for further analysis.

You can also contact AVG customer care and troubleshoot the situation via phone call or chat session.

Thank you for posting in forum.