ALSO - every time I start up TB I get the webpage to donate money (https://www.thunderbird.net/en-GB/thunderbird/102.0/eoy/) .... is that meant to happen all the time or is it related to the problem that I am having?

I have TB 102.13.0 (64-bit) with a bespoke location for the profile (in my Dropbox folder).

Not supported! </blockquote>

I don't understand what you mean by not supported - Changing the tags or the settings are not supported?? That can't be correct as you must be able to change settings when you have to update your password on a regular basis. OR This version of TB is not supported in this forum? OR Bespoke locations aren't supported - https://kb.mozillazine.org/Moving_your_profile_folder_-_Thunderbird Please can you explain? Thanks

I believe what he meant is that use of cloud services is not supported.

I mean your configuration is not supported. I fail entirely to understand how I was no clear. I even went to the trouble of quoting your use of drop box in the reply. I would hardly be trying to tell you the current release version was not supported.

Thunderbird struggles to function without serious issue on a local NAS or a network drive (network saturation), without the added overhead of syncing. Total corruption of the profile is the most likely long term result of using cloud services as they are an order of magnitude slower that local network resources.

Use of streamed backups on the Thunderbird profile is also not supported as Thunderbird just does not have the modern file locking and caching abilities to cope with any other software messing in it's profile while it is running. Likewise you will find this forum full of suggestions to folk to disable on access scanning in internet security suites/Antivirus programs to prevent issues with data integrity.

The issue you are currently seeing will be the surface of an iceberg of data corruption, duplication and other, til now, hidden issues. I have seen these smart synced profiles make multiple copies of the storage files (Often copies that are never referenced again) Search the web of those folk with hundreds of prefs.js files complaining that Thunderbird does not save their changes. Or those complaining that they have issues with the same mail being downloaded over and over (pop accounts) or even those that appear to have lost the mail in a folder because it is corrupted.

It used to be that antivirus programs were the greatest source of data corruption. Personally I am thinking that the cottage industry in synced profiles is fast catching up. Thunderbird sync can not come soon enough, but like profile import it will probably be unable to sync password, making it largely useless.

You might want to have a look at how many redundant pref.js files you have in your profile. My guess is many, each with a number to make it unique, created when your sync created a contention issue. The copies are never referenced because Thunderbird is hard coded to use only the prefs.js file, but the data is saved.

Thanks for your latest reply, Matt. Please excuse us types who only use forums in desperation and don't always get the shorthand!

From my understanding now, I think this boils down to TB not being happy with using any location for the profile other than the standard location on, what is for me, my system drive of C:\Users\UserName\AppData\Roaming\Thunderbird. Even though there is a post on the KB https://kb.mozillazine.org/Moving_your_profile_folder_-_Thunderbird that seems to indicate this - maybe I have read this wrong as well! And just to spell it out for my brain, it is because of the time lag of reading and writing to a different drive. Like lots of people, I keep my data separate from my system and in my case all in Dropbox, so I wanted to do the same for my email folders - to have a synced back up in case of HDD failure. I will have to plan a new way of backing up and revert to the original location for the profile. Maybe even looking at a different email system. Thanks for taking the time to explain - it is appreciated.