You have this volume you want to backup but this is a live volume : some apps are constantly writting to it and you need to backup a snapshot.
On the command line :
-Lets create a volume shadow copy : vscsc.exe -wait f:
In CloneDisk :
-lets assign a x: logical drive letter to our shadow volume copy (step 1 below) -> this step is optional
-lets backup this x: logical drive, or dosdevice if you did not assign a letter, to a file (step 2 below)
You can now restore from this file but also open it in 7zip, mount it with imdisk, etc.