Recently got error 109 when running time machine backups wirelessly from macbook pro to 1 TB My World Book Network Storage.
No issues previously for many weeks and a month or two.
Recently upgraded Network Storage Firmware with successfull backups.
Found nothing on google that was really helpful.
Found nothing this support site very helpful.
Although, Time Machine is configured for hourly backups, more importantly, configured to remove older backups when storage limitations are met…THIS IS NOT POSSIBLE USING QUOTAS on 1TB Network Storage MY World Book Device.
After removing quota and/or increasing quota for WD_Backup error 109 and hanging issue was completely resolved.
Time Machine is working again, previous backups are visible and available!
Be Advised Quota Issues Still Remains:
If you using a quota for your mac backups under WD_Backup, then Time Machine doesn’t even realize/read quota restrictions.
In other words, Time Machine sees the entire drive available for backup (1 TB versus Quota Parameters Set By Admin).