Disk Drill usually detects disk errors by reading system logs of your internal and external disks (including physically connected mobile devices). Suspicious log records is not something your regular disk monitoring software will alert you about. Disk Drill does. In most cases it’s a system-level error that may signal you of potential hardware problems long in advance.
If suspicious logs appear for the first time and you don’t see any visible signs of disk failures, simply clear these logs with the following terminal command
sudo rm -r /var/log/asl/*
and then reboot. If the error appears again, then one or more of your disks probably have hardware issues. In this case, consider creating a backup directory and moving all important files to it asap.