FRITZ!Box 6490 Cable Service - Knowledge Base

FRITZ!Box 6490 Cable Service

Windows offline synchronization fails when using storage (NAS)

Windows offline synchronization fails when it attempts to save data stored on USB storage devices connected to the FRITZ!Box. The error message "The process cannot access the file because it is being used by another process." is displayed in the Windows Sync Center for each file it attempts to copy.


  • Windows offline synchronization can only reliably copy data to another Windows computer. Errors may occur when using it with network drives on computers with macOS or Linux and NAS (Network Attached Storage) systems such as the FRITZ!Box.

1 Issue is being examined

The issue is currently being examined by our development department. If an update for the FRITZ!Box can correct this behavior, we shall make a corresponding FRITZ!OS update available for the FRITZ!Box.

If you are leasing your FRITZ!Box from your cable provider, then your cable provider will make the FRITZ!OS update available, and not AVM. Refer to your cable provider for possible release dates.