FRITZ!Box 3390 Service - Knowledge Base
Incorrect storage capacity shown for USB storage device
When you connect a USB storage device to the FRITZ!Box and configure it as a network drive, a computer displays a higher storage capacity (size) for it than is actually available.
Total storage capacity of storage devices connected to the FRITZ!Box is shown
All storage that is connected to or configured in the FRITZ!Box (for example USB storage devices and online storage) that can be accessed using the Server Message Block (SMB) protocol is displayed in the shared folder \"\\fritz.box\FRITZ.NAS" in the home network. If a subdirectory of this folder is set up as a network drive, the computer's SMB client can only determine the storage capacity of the entire network folder.
Therefore, the computer displays the total storage capacity of all storage devices connected to the FRITZ!Box as the available capacity of all subdirectories that are configured as network drives, for example individual USB storage devices. This is not an error on the part of the FRITZ!Box.