What is the authentication on the gmail POP account? If it's 'normal password', you must allow access by 'less-secure apps' in the Google account settings. Even if it's OAuth2, some users have found you must make the same setting. Another possibility is that when you copied the profile from Windows to OS X, the pkcs11.txt file in the profile folder wasn't deleted, as this can block stored passwords from being accessed.

Hi... 'Less-secure apps' is on in the account settings. I deleted pkcs11.txt. I restarted TB and it created a new pkcs11.txt with proper mac directories in it. No change. "xxxxx@gmail.com: Connected to pop.gmail..." on bottom of screen (xxxxx is a substitute for actual email since I have 15 or so addresses there) and it sits there for several minutes showing that, then that fades away afterwards doing nothing...

I'm stumped...

I just successfully sent an email from TB to my icloud email through Gmail.... but cannot receive. Weird...

What's the authentication on the account? Make sure cookies are allowed in TB Preferences/Privacy, set the authentication to OAuth2 in Tools/Account Settings, Server Settings, and also in Outgoing Server (SMTP), Remove any passwords or oauth:// entries in Preferences/Security/Passwords/Saved Passwords, restart TB, and enter the regular account password in the OAuth browser window when prompted.

Hi. Cookies allowed. Changed all gmail accounts to OAuth2, and deleted all saved passwords. Restarted. TB still ran through the accounts with "xxxxx@gmail.com: Connected to pop.gmail..." on bottom of screen with No prompting for a password which is strange....

I don't know if this is an issue with 75b1 on OS X or gmail POP. I can add a gmail IMAP account to 75b1 on W10 that works fine. I would recommend you try to add the account in a new profile with the release version, 68.6.