Windows Defender Quick Scan started stopping partway through and asked me to restart it, but the same thing happened again afterward. Microsoft Safety Scanner also stops randomly without showing an error. Malwarebytes found a few potentially unwanted hijacker files, but its deeper scan of roughly 700,000 items found nothing else, and HitmanPro was clean as well.
I ran DISM and SFC, which reported and repaired corrupted system files, then restarted the computer. However, Defender Quick Scan still will not complete. I also tried rolling back or resetting Defender definitions, but received error 0x80070005, indicating access was denied.
Does this sound more like malware or a Windows issue, and what steps can I take to get Defender scans working again?
2 Answers
Windows Defender’s real-time protection continuously checks files as they’re opened or used, so if Malwarebytes’ full scan and HitmanPro both came back clean, there may not be an active infection. Running another scanner can help confirm things, but multiple security programs aren’t usually necessary for routine protection. For a specific suspicious file, you can also submit it to a reputable online malware scanner.
The fact that several independent scanners either completed normally or found nothing significant points more toward a current Defender or Windows glitch than an infection. The 0x80070005 error means the definition-reset operation was denied, so repairing Defender components or installing the latest Windows updates may be more useful than repeatedly scanning. Keep backups current before making system changes, and avoid running several real-time antivirus products together.
I tend to run scans because I’m cautious, and I installed the other tools mainly to see whether they would fail too. Since they also completed successfully, this does seem more like a Windows or Defender problem than malware.