I've been having this problem for a month or two while running McAfee Antivirus Plus on Windows 10 64-bit:
Several times a day, something (presumably WebAdvisor) puts several megabytes of text into a log file in directory C:\ProgramData\McAfee\WebAdvisor\DownloadScan.dll (maybe once or twice a day). Yes, the name of the directory is DownloadScan.dll. Then after several days to a week or two of this, that log file will suddenly start growing without stopping; those same lines of text are put into the log file every 12 milliseconds, so the file grows quickly. The line of text that subsequently fills this file (up to many gigabytes until I catch it) is always of the form:
[ERR][20200414 06:58:10.005][PipeName.cpp@108]: Failed to open WebAdvisor registry key
The time increases by 12 ms. each line. The name of the log file varies, but is of the form:
log_002700410033001A0003.txt
The only way to stop WebAdvisor from eating up my hard drive with these log messages is to log off, then log back on, and finally delete the file manually.
Also, if I open the McAfee control center, click on the gear in the upper right, and select McAfee WebAdvisor, absolutely nothing happens at all - no dialog comes up. Perhaps this is some sort of clue?
Does anyone have any idea how to stop this annoying log file behavior?