You didn't say how you set up Thunderbird to connect to the new host instead of Gmail. Please provide the IMAP/POP and SMTP settings you created for the new host. If you removed all the email from Gmail, to another server, and have not set up an account in Thunderbird to connect to the new host server, then Thunderbird can't connect to the new location.

All emails were migrated to a new host. Old Gmail settings, and file have been deleted. I have used the IMAP settings as provided by my new host.

Using the identical settings that I have used in Thunderbird, both outlook and eM Client can see the emails in the folders. Thunderbird can see all the folders, even new ones setup since the migration, but they are all in italics with no emails visible. The host provider had the same results when they did the same thing.

When I right click folder properties, go to quota. On the Inbox folder, it tells me that I have used 20gb of 30gb quota. and how many total emails are on server. In General tab it tells me how many emails are in Inbox. When I right click properties on on the italic folders, there are zero emails in General. In quota it says " Quota information is not available because the folder is not open.

I will be grateful for any suggestions or fixes.

Ok, sounds like you have the account set up. You may need to 'subscribe' to the folders you want to see in Thunderbird. I know this article is about Gmail and you are not using Gmail, but the section about subscribing should help. Subscribing to folders and synchronizing messages in https://support.mozilla.org/en-US/kb/thunderbird-and-gmail If that's not it, can you post a screen shot? This general information about synchronizing with IMAP may be helpful. https://support.mozilla.org/en-US/kb/imap-synchronization

Ok, sounds like you have the account set up. You may need to 'subscribe' to the folders you want to see in Thunderbird. I know this article is about Gmail and you are not using Gmail, but the section about subscribing should help. Subscribing to folders and synchronizing messages in https://support.mozilla.org/en-US/kb/thunderbird-and-gmail

Thanks again for your reply.

I think we're getting somewhere. I looked in Subscribe. In there I can see all the folders with no check in the check box. When I tried to subscribe and click ok, Nothing changed. When I went back to subscribe, the folder was again unsubscribed. I scrolled down the list of folders, and lo and behold, there was another list of the same folders with the subscription check box checked, below.

I picked one of the those folders and unsubscribed. Went back to the top of the list. Found the corresponding folder in the first list and subscribed. All the emails have appeared. I'll now go back and unsubscribe to all the folders at the bottom, and subscribe to the first lot at the top. That should sort out that issue.

The question now remains, why do I have two lists of the same folders?

The only other thing I need to resolve is deleting the double emails. I have the All Mail folder plus the other folders which came over from Gmail, and now I'm guessing most of those emails in the other folders. Thats why my data file has doubled since migrating over. What's the best way to identify the exact doubles in All Mail so they can be safely deleted without mistakenly deleting the ones in folders.

Merry Christmas from Australia

Ah, indeed, getting somewhere. However I am not sure at all why you have two lists. Could Thunderbird be still somehow listing the original Gmail account folders (which you got rid of in account settings?) as well as a list of the ones in the new host - the same migrated folders. Guessing. If you read up on All Mail generally, and the article I referred to earlier, you may find clarification regarding duplicates. I understand that All Mail includes all the messages in all other Gmail labels/folders - it's peculiarity of Gmail. Read up on it to be sure, but you may be able to delete the whole of All Mail. I never 'subscribed' to All Mail myself, because I didn't want to have two of everything in Thunderbird. Merry Christmas from Canada! or Boxing Day where you are.

Thank you AgnesRM for your help. It solved the problem.

Neither the emails hosting support team or a local tech who logged into my system could work out the problem.