Danw12321 asked the Answer Line forum if it's safe to work, say, on a Microsoft Word document, while scanning for malware.
Absolutely. Editing a Word document will not affect the scan's results, and the scan won't hurt the Word document. Even if you did something inherently dangerous, like downloading a suspicious file from an untrustworthy Web site, the real-time module for your antivirus program is as likely to catch it while scanning as at any other time.
The downside: It will affect performance. The scan will take longer, and during that time, everything else will go slower. Whether the speed hit will be enough to bother you depends on your hardware, software, and temperament. I seldom notice any sluggishness when scanning--and when I do, it's only a mild annoyance. And my PC is underpowered by today's standards.
If you find that it bothers you, scan when you're not using your PC.
Read the original forum discussion.