Why do techs scan viruses in safe mode?

Safe mode only load MS system files. So, everything you installed including malwares are not running and that's the best way to scan and clean.. especially, rootkits and malwares with hooking capability.

There are security product like Spyware Doctor informs the user to scan in safe mode ( if the malware cannot be clean because it's running and hooked with a legitimate process) and doing it, will completely help the product clean the infected pc.

Why do techs scan viruses in safe mode?pop up blocker

To add to the above, some of the virus' exploit capabilities that do not exist in safe mode, for example, certain ways of configuring the system to auto-load programs at startup, a feature that virus' frequently take advantage of, do not function like they do regularly. A virus that can spread across networks needs to be eliminated from machines while they are disconnected, otherwise you will wind up chasing the virus from machine to machine.

Why do techs scan viruses in safe mode?systemworks

Scans are more effective because the system loads minimal drivers.
Many times we will need to troubleshoot our computer. Whether it is to remove the final traces of a Virus or a piece of Spyware that will not go away, we may find it easier to perform these tasks in Safe Mode. While in Safe Mode, Windows will only load a very basic video driver along with just the essential files needed to run the operating system. Some functions, such as Network connectivity, will not be activated in Safe Mode. This will then allow you to perform troubleshooting techniques to deal with various problems that may arise.
You will notice that you cannot delete files that are in use. When you boot into safe mode, windows only runs the bare minimum of programs. It does not load device drivers, etc. So, it is less likely that a virus will be running, enabling you or the tech to delete the files.