Remove and restart Time machine backup

1. Removal via Time Machine AFP share (All firmwares)
(a) Under the Finder menu select Go > Connect to Server

(b) In the Connect to Server enter the following URI, replacing [ReadyNAS] with the IP address or hostname of your ReadyNAS.

afp://[ReadyNAS]

(c) When prompted for a username and password enter the following credentials:

Connect as: Registered User

Name: ReadyNAS

Password: (previously defined through Time Machine setup in Frontview)

(d) Select the appropriate sparse bundle and delete it via Finder:

Thanks for the advice!

Two follow-up problems:
a) Time Machine sparse bundle A (340 GB) - when I try to delete it using Finder after some time I ger the error message:
"The operation can't be completed because the item "token" is in use".

b) Time Machine sparse bundle B (203 GB) - this file is "Locked". When I through "get info" try to un-mark the "Locked" box I get
the colorful spinning ball and after a while the box is marked again automatically.

In my NAS setting I have given manually a max quota for Time Machine backups to 700 GB, but to the right of this box I find
a maximum given 100 GB. What does this 100 GB mean? It is not described in the Raidiator Manual pg 69 on for ver 4.1 dated December 2011.
After all I have run the Time Machine for 1-2 years with two Macs with little problems and well above 100 GB (but less than my given 700 GB)
although the backup have had "integrity problems" a few times which results in a simple restart of the backup.

Perhaps try connecting to CIFS as the admin user and going to the hidden .timemachine folder on the c share and deleting it that way.

There is probably only about 100GB free on your data volume. If you want to change the quota 100GB is the max you can set it to without freeing up some space.

Thanks again for your advice!

Actually for item a) above I managed get around problems with "token" by simply
restart NAS and Mac a few times - and could delete the sparse bundle successfully.

For item b) I have managed to un-lock the file from the ReadyNAS account.
But I cannot change permissions.
And I cannot delete it either, which I could we the other sparsebundle.
Get complains about I do not have permissions.

Followed your advice to login as admin through CIFS and look in folder C.
Here I do not know how to see the hidden file .timemachine.
I tried to change settings in Macs Finder using terminal:

$ defaults write com.apple.Finder AppleShowAllFiles YES

and re-launch Finder but did not help me see hidden files.
Is there some setting on the NAS to make hidden files visible?

If you've mounted the c volume you could open the Finder, and in the Go menu select Go to Folder and type "/Volumes/c/.timemachine" (no quotes)

It works, but extremely slowly. The 200 GB sparse bundle file is deleted at a rate of about 4 GB per hour.
And this is over night and no other traffic on my LAN.
The previous sparse bundle (for my other Mac) was deleted from ReadyNAS account and deleted 340 GB
at a speed of about 40 GB per hour.

Any comment on this behavior?

Just managed to delete the full TimeMachine/Sparsbunle from my ReadyNas Duo. Had the same issue, manage to start deleting but it was extremely slow... Took a couple of evenings with trial and error...

This is what I tried but gave up on
- Delete from Finder (after connecting through CIFS, AFS etc). Timed out.
- Using Mac Terminal. Delteted 1 file per 10 seconds. 32k files. Would have taken ages.
- Went into the Linux shell on the Duo using rm... But same, took an awful long time.

This is how I got around it.
- Downloaded FileBrower to my iPad (works on iPhone as well)
- Connected to the ReadyNas as admin
- Change the setting in FileBrowers to show hidden and system files (you will not find .sparsbundle otherwise)
- Started delete from FileBrowers. 32k files took about 10 minutes to clear :-)