I installed Thunderbird for a client today after his copy of Outlook Express kept giving him grief with his Gmail IMAP. I’ve always been very happy with Thunderbird, as far as a light mail client goes, it covers most of the bases.
I noticed a peculiar error today whereas it would prompt for a password everyonce and a while. Even though I had saved it to the Password Manager. Apparently this is a common issue.
From what I’ve distilled the best thing you can do are the following.
Go to your IMAP account settings and bring increase the time between checks on the Gmail server. A change from five minutes to ten has helped some users from getting the constant request to reauthenticate. Others have up and switched to POP, not a long term solution, but you can always set your gmail to archive. The other solution that I came up with was to go to your Gmail web page, and go to the bottom where it shows the clients checking your mail. Verify you don’t have another device, like an iPhone or smartphone checking your imap mail as well. This can cause Gmail to detect too many users and refuse your password.
There is no definitive answer from google yet on this one, so your best bet is to play with your settings and see if you can make it bearable.
Update: Found some info on the Google Apps Site: the unlock captcha part seems to ask for an email address which means you can use your normal Gmail address as well.
Status This is a known issue. We’re currently working on a solution to address it.
In most cases, it will help to follow the recommendations in the Gmail Help Center including clearing the captcha.
To clear the captcha, visit https://www.google.com/a/yourdomain.com/UnlockCaptcha. Be sure to replace ‘yourdomain.com’ with your actual domain name.
This issue might also be resolved by changing the strength of your Google Apps account password. In this case, we would recommend using a strong password that contains more than eight characters.
If you are continue to be prompted for your password and need to clear your captcha often, please contact us and provide screenshots, the time that you received this error for several examples, and the exact error message that you are receiving.