When creating an image of selected drives I do not run other programs or apps but wonder this is necessary to prevent possible interference during the image creation? I realize that in most operating systems numerous apps and services are running in the background which presumably do not conflict with the image creation process. I have an image being created now and am running my Firefox browser to see if there is any indication of interference or conflict. Wondering what others do and if Macrium authors speak to the issue.
Macrium uses Volume Shadow Copy so it can backup data even if it's being used. I have automatic backup set up and don't pay much attention about my computing during backup operations. So far I've had no problems. More info about VSS: https://docs.microsoft.com/en-us/windows-server/storage/file-server/volume-shadow-copy-service
As an example.. using vss.. once your backup is running... You could delete all your files... Get a virus... make any changes... These changes won't be in your backup that is currently running.
That is correct. A VSS request to the Windows OS will freeze a snapshot of the entire FileSystem (once all database writers have responded and cached out their databases to the disk, making them "consistent"). Once this snapshot has been frozen, all changes from that point on are maintained elsewhere on the System and the frozen snapshot is available to the requester. When the requester has finished with the FileSystem snapshot, it informs the OS and the snapshot is deleted. At this time, all FileSystem changes are re-integrated (and based on your scenario, infecting the System) into the full System.