In many instances, in order to backup
In some cases, third-party encryption programs may offer a setting that will allow you to mount a drive as removable media. You can see an example of this in the preferences for VeraCrypt shown below.
Backblaze is not able to back up a drive if it is seen as temporary or removable media, and can only back them up if they are seen as local disks. If the encryption software you use offers the option to mount volumes as removable media, as shown above, you will need to deselect this option in order to allow your drives to back up to us.