The restore feature (General Restore / Full Restore) on My Book World Edition II has a serious bug. It wrecks the WD_Backup user, so Time Machine stops working, making it impossible to create or access any backups. This bug is verified on current firmware version 01.02.14.
When Time Machine is started, it shows the error message: “An unexpected error occurred (error code -6584).”
When trying to change backup disk in System Preferences, the user WD_Backup and correct password are not accepted.
In MBWE web interface it’s impossible to change the WD_Backup users password. An error message “Failed to change the password for ‘WD_Backup’!” is shown.
What happened: The restore deletes WD_Backup from /etc/passwd and recreates the user entry, messing it up somehow. It misses out a colon ( : ) between the password placeholder “x” and the user id “502”. This makes it impossible for Time Machine to access or generate backups.
The user entry in /etc/passwd can be repaired by running:
sed -i ‘s/:x502:/502:/g’ /etc/passwd
The firmware bug in General and Full Restore can be fixed by running:
sed -i ‘s/“502:/”:502:/g’ /proto/SxM_webui/admin/tools/generalRestore.php
sed -i ‘s/“502:/”:502:/g’ /proto/SxM_webui/admin/tools/fullRestore.php
So next time General or Full Restore is run, it will not make the same mistake again.
I wrote a little script that can automatically repair the WD_Backup user and fix the firmware, bringing Time Machine back to life. Here is the link.