Archiving Outlook PST - "The pipe has been ended"

Does anyone know why this error occurs repeatedly when trying to archive an Outlook 2010 PST file? The archive had been running fine for a couple of years up to now.

 Unable to access Outlook folder myuser@blueyonder.co.uk/<IPMRoot>. The pipe has been ended. (Exception from HRESULT: 0x8007006D)  
 The folder info@mydomain.com can not be accessed. The pipe has been ended. (Exception from HRESULT: 0x8007006D)  
 The folder info@mydomain.com/Drafts can not be accessed. The pipe has been ended. (Exception from HRESULT: 0x8007006D)  
 The folder info@mydomain.com/Inbox can not be accessed. The pipe has been ended. (Exception from HRESULT: 0x8007006D)  
 The folder info@mydomain.com/Junk can not be accessed. The pipe has been ended. (Exception from HRESULT: 0x8007006D)  
 The folder info@mydomain.com/Sent can not be accessed. The pipe has been ended. (Exception from HRESULT: 0x8007006D)  
 The folder info@mydomain.com/Sent Messages can not be accessed. The pipe has been ended. (Exception from HRESULT: 0x8007006D)  
 The folder Outlook can not be accessed. The pipe has been ended. (Exception from HRESULT: 0x8007006D)  
 The folder Outlook/Conversation Action Settings can not be accessed. The pipe has been ended. (Exception from HRESULT: 0x8007006D)  
 The folder Outlook/Inbox can not be accessed. The pipe has been ended. (Exception from HRESULT: 0x8007006D)  
 The folder Outlook/News Feed can not be accessed. The pipe has been ended. (Exception from HRESULT: 0x8007006D)  
 The folder Outlook/Quick Step Settings can not be accessed. The pipe has been ended. (Exception from HRESULT: 0x8007006D)  
 The folder Outlook/RSS Feeds can not be accessed. The pipe has been ended. (Exception from HRESULT: 0x8007006D)  
 The folder Outlook/Sent Items can not be accessed. The pipe has been ended. (Exception from HRESULT: 0x8007006D)  
 The folder myuser@blueyonder.co.uk can not be accessed. The pipe has been ended. (Exception from HRESULT: 0x8007006D)  
 The folder myuser@mydomain.com (new) can not be accessed. The pipe has been ended. (Exception from HRESULT: 0x8007006D)  
 The folder myuser@mydomain.com (new)/Drafts can not be accessed. The pipe has been ended. (Exception from HRESULT: 0x8007006D)  
 The folder myuser@mydomain.com (new)/Inbox can not be accessed. The pipe has been ended. (Exception from HRESULT: 0x8007006D)  
 The folder myuser@mydomain.com (new)/Junk can not be accessed. The pipe has been ended. (Exception from HRESULT: 0x8007006D)  
 The folder myuser@mydomain.com (new)/Sent can not be accessed. The pipe has been ended. (Exception from HRESULT: 0x8007006D)  
 The folder myuser@mydomain.com (new)/Sent Messages can not be accessed. The pipe has been ended. (Exception from HRESULT: 0x8007006D)

@itm60

Typically this indicates some corruption within the PST itself. Outlook ignores a lot of errors in PST files that can cause MailStore issues. I’d suggest backing up the PST, then running ScanPST to correct the errors.

Note that you may have to run ScanPST several times, I would suggest running it repeatedly until it completes a scan without errors. For more information on repairing PST files, check the following link:
https://support.microsoft.com/en-gb/office/repair-outlook-data-files-pst-and-ost-25663bc3-11ec-4412-86c4-60458afc5253?ocmsassetid=ha010354964&ctt=1&correlationid=77e4e9b3-d9cf-4e84-bcdf-e7de5c9a6483&ui=en-us&rs=en-gb&ad=gb

Once the PST has been repaired, re-execute the archive process and see if you are able to complete the archiving task at that point.

I’ve created a brand new Outlook profile, with a new data file, but am continuing to get the “pipe has been ended” error. If I use POP3 instead of IMAP I don’t get the error, but this isn’t ideal as I access email from multiple devices.
I also don’t get the error with another email account - Mailstore only has a problem with an @blueyonder.co.uk email account (hosted by Virgin Media in the UK). I’ve spent alot of time deleting older emails, in case the issue is size-related, but it doesn’t help.
???

I would suggest you “Google” Virgin Media and Blueyonder in relation to email accounts. You should have received a message from Virgin that they were being orphaned around 2020. Nothing to do with Mailstore but blocked/lost? by Virgin/Blueyonder.

The Blueyonder email account is still active at Virgin Media, and webmail access to it is still possible
???
Edit: and Outlook 2010 has no problems accessing the account via IMAP. I only get the error when I try to run the Mailstore Home archive.