This is what I think you are telling me: You have your own web hosting account and switched domain server from Google to Namecheap to point to the web host. If that is what you're saying, then all is fine because Thunderbird goes only by the domain name, not the IP of the domain server. That is, if the email was yourname@xxxx.com with Google and it remains yourname@xxxx.com with Namecheap, all is well.

Hi David. I'm glad that you think that you know what I'm telling you, as I have no idea what you're telling me! (sorry, I'm only beginner-intermediate tech savvy) Here's my situation: I had an email address set up for my business about 20 years ago, and have used it ever since. As of Wednesday I wasn't able to log in, and discovered that my Google workspace account had been suspended (I didn't even know that I had one). I have since found out that google had been emailing the original administrator (who is long gone) to let them know that services would be discontinued. I can't get into my account and it is impossible to get anywhere with google. I've put about 20 hours in so far and I desperately need my business email to work. Last night I discovered that I can switch my google business email address to be (hosted?) by namecheap (my registrar). I've done so and I want to set it up to work with thunderbird. It is the exact same email address that I already have set up in thunderbird. All of my emails and subfolders are in it, and I'm concerned that if I set up the new one it will overwrite the old one and I'll lose everything, as it is the exact same email address. Thanks so much for responding

What David is trying to tell you is something like this analogy.

Your email address is somewhat like your physical address. What you have done is cancel your contract with DHL to deliver parcels to your house and appoint FedEX to deliver parcels. So what would you need to do in that scenario is nothing as the contractor knows where you live.

The same is occurring here. You have canceled your contract with Google and appointed Namecheap. They will manage the routing of information, or should. What you need to do is again nothing as your address has not changed. Just the delivery agent has changed.

That is the over simplified version, and holds if your hosted email server name has not changed. What do currently have set as your mail server in Thunderbird? What does name cheap say you should use for their hosted mail? This bit is important. Are name cheap transferring mail from google? Generally the answer to that is no! so contunie if that is the case.

Is your account IMAP? If the answer to that is yes, download the import export tools addon https://addons.thunderbird.net/en-US/thunderbird/addon/importexporttools-ng/?src=ss

I have linked to it, but it is best searched through on the addons entry on the tools menu for installation.

Use this tool to export all the mail in your existing account that you want to keep to EML or MBOX files. IMAP accounts are inherently synchronized to the server, so existing mail, unless brought over by namecheap will be lose in the transfer and the first sy6ncronisation after the change will see it all deleted as the new server has no mail on it.

You can immediately re-import the mail to the "local folders account" but this work much faster and more reliably than actual drag and drop within Thunderbird due to the synchronization that must occur in the background.