Yes, it is completely possible. Software can back up your files in a “hot” mode when it saving copies of your files already opened by another application. This is very useful option, as you can keep the workflow of data when you perform the backup. It can be most actual when you backup databases. The engine used for this technique is a Volume Shadow Copying service (VSS) performing the snapshot of any file already opened.
These are conditions under that the “hot” backup is available:
See also: FAQ | Program Installation and Usage:
⇒ How can I restore a specific file?