A specified logon session does not exist. It may already have been...

Just to clarify, you wish to backup the data stored on the network share to an online service correct? However it fails with that error when trying to? Just a question, when the online backup sequence starts do you have a session open with your network share using your account?

My guess, is that it is trying to backup the data however your computer has yet to authenticate with it therefore it fails.

A possible work around that you may wish to try is to map the network share to a drive letter and then run the backup on the mapped drive (e.g Y:\ or Z:\... etc) rather than the UNC path (\\DLINK-9FF8CF\Volume_1)

Follow this tutorial to map the relevant network share you wish to backup to a drive letter and then please try to run the backup using the mapped drive instead of the UNC path.

Map Network Drive - Please follow METHOD TWO ONLY

Hope This Helps,
Josh :)

murfeezlaw said:

Hi Josh, thank you very much for the reply. Yes you are correct with your above assumption. I had tried previously backing up the NAS using a drive letter and the online backup company (SOS Online Backup) suggested that I use the UNC path instead. I did try it again though. I mapped L: to \\DLINK-9FF8CF\Volume_1 and I received the exact same error.

I'm not sure what you mean by this...when the online backup sequence starts do you have a session open with your network share using your account?

Do you have any other ideas? :)

What I mean is, do you have a window open where you are looking at the files before they are backed up... Hmmm

As a test, can you change the everyone permission to full control temporarily and then try the backup. This will help us determine if this is an authentication issue. If it does then it is an issue with permissions. If not then most likely caused by something else. My next step will be to test DNS resolutions.

Josh :)

murfeezlaw said:

I have in the past but I just closed all running applications and Windows Explorer and tried a backup and received the same error.

I changed the permission settings for Everyone. When I click on Edit, the Permissions window pops up, I select to Allow Full Control, all check boxes get selected. However when I click Apply all check boxes unselect. Is that normal. When I click the Advanced button on the Security tab and check permissions it appears that Everyone has full control.

Thanks Josh

As long as advanced settings shows it being full control then you should be good to go. Edit permissions typically have a limited view of permissions.

Did the backup work?

Josh :)

What is the service that you are using to backup? Are you using a particular application to complete this?

Have you tried completing the backup using the IP address instead of the hostname? For example:

\\192.168.0.10\Volume_1

Josh :)