More Information:
It works on the Admin Account.
The same emails that failed to process under Thunderbird and CSE on a STANDARD account have downloaded okay on the Administrator Account. The Admin and Standard accounts have the same Thunderbird setup but obviously different profiles.
Hope this helps with your diagnosis.
Regards Peroulades
Hi,
Working on the success of the process in the Admin Account I decided to create a new profile for Thunderbird in the Standard Account with the same setup as the previous one.
Hey Presto, it works and downloads the large emails.
So perhaps this was just a slightly corrupt Thunderbird Profile (one that had passed through lots of Thunderbird version updates and CSE for that matter)
I will monitor the situation.
Regards, Peroulades
The problem has returned and since there appears to be no solution or even acknowledgement of a problem, I have uninstalled CSE for good.
Regards