Why is a full scan taking so long?

I recently switched to BitDefender. My first scan took several hours (I don't know how long, since I had to cancel and restart the scan midway through). A few days later, I ended up doing another scan and it finished within 40 minutes.

Today, I ran Spybot Anti Beacon to disable Windows telemetry/tracking. On a lark, I decided to run another scan. It hasn't found anything, but it is going for over three hours now. 

What is with the discrepancy in scan lengths?


  • Yes, because Installed applications that have been scanned and deemed as safe will not be repeatedly scanned, unless their behavior has either changed or a malicious intent has been spotted. As such, only unknown applications will be scrutinized by the full spectrum of antimalware technologies.