From the web interface, move the Inbox messages to another folder, then add the account as POP type in TB, so that only the Inbox messages are downloaded. TB will default to IMAP when you add the account, so just click Manual.config. and enter POP settings:

http://kb.mozillazine.org/Using_Gmail_with_Thunderbird_and_Mozilla_Suite

I tried those steps. On the web, I moved the existing messages to a folder. I set up Thunderbird as a POP account. When I told it to Get Messages, It went out and grabbed all the messages from the email account.

Did TB download all the Gmail folders, including Sent etc.? When you select Tools/Account Settings/gmailaccount/Server Settings, is the Server Type listed as POP?

Yes, it downloaded all the emails and folders. I did some checking on the Gmail website and found a setting there for POP3: Download ALL, Download from this point forward, Disable POP. It defaults to download all. I changed it to Download from this point forward. That took care of the issue. Three steps are required for Gmail: 1) Download TB and set the account to use POP instead of IMAP. 2) Log on to your Gmail web account and go to Settings, Forwarding and POP/IMAP. 3) Select Enable POP for mail that arrives from now on.

After doing these steps, start Thunderbird and it should only receive new email messages.

I will mark the issue solved, but wanting to provide you what I learned to help others in the future. Thank You , Greg Nackers