Hi there, 

I have a folder which I cannot rename, delete, delete messages or change flags. It just wont let me do anything with it. I can open the messages.

Here is the sort of errror I get whenever I try to edit it.

Cannot move the item. The server responded 'NONEXISTENT] Mailbox does not exist

I am using the same mailbox I have always used and all other folders are fine.

Thanks for your help!

Hi,

What type of account are you using in Outlook? Exchange, IMAP or POP3?

If the folder is available on the webmail, check if you meet the same issue when editing the folder. If there is no such issue on web, the local Outlook Data File may have been corrupted. For .ost files, I suggest you rename the .ost file to .old, Outlook will generate a new one to sync with the server. For .pst files, I suggest you run Scanpst.exe to repair it:

https://support.microsoft.com/en-us/kb/272227

You can also try the MFCMAPI tool to edit the items in this folder, check if the problem persists:

https://mfcmapi.codeplex.com/releases/view/127629

Regards,

Melon Chen
TechNet Community Su