I presume there will be consequences should this reach 100%!

Yes, typically you won't be able to receive messages anymore, and you may not be able to send messages either.

My mail server is showing no issues of quotas being reached.

If in doubt, check with your email provider.

Is this an issue that relates to Thunderbird quotas?

Thunderbird itself has no quota.

Can anyone advise how I can reduce the 103mb total that is being shown?

You can delete messages you don't need to keep anymore. And for messages you want to keep, you can move them off of the server to your 'Local Folders' account.

Thanks for your reply - much appreciated.

I have contacted my website hosting company to ask for their advice.

I will post their reply when I recieve it.

I've been able to access my email accounts at my hosting company, deleting the messages held there.

This has deleted all messages in my Thunderbird Inbox too. Sent items are still listed.

I have right clicked Local Folders in Thunderbird and created a new folder called Inbox Transfers.

Am I right in thinking that if I put messages in there from my present inboxes, they won't be deleted next time I delete messages at my hosting company? In this way, I can keep messages indefinitely?

Many thanks.

Mike

I've been ... deleting the messages held there. This has deleted all messages in my Thunderbird Inbox too.

This is how IMAP works, so it shouldn't come as a surprise.

Am I right in thinking that if I put messages in there from my present inboxes, they won't be deleted next time I delete messages at my hosting company?

Yes, that's the idea.

In this way, I can keep messages indefinitely?

You should still create backups.

Thanks, Chris.