Google’s Gmail service offers options to access your mail through an e-mail client, but if you configure Apple’s Mail client to access your account, you may run into an issue where the account does not update with new messages. While the Connection Doctor and Activity windows show no errors for accessing the Gmail servers, even though new messages show in Google’s Webmail client, they do not show up in Mail.

This problem can prevent you from receiving important messages, so if you are experiencing it, then there are several things you can do to at least work around the problem.

Use Webmail

Of course, the first option is to forego the use of an e-mail client and access Gmail through the Web. This offers a number of unique services from Google, but may not be the most convenient option. However, if you are having trouble with an e-mail client, then this will ensure you can see your new mail, until the client problems are fixed.

Rebuild mailboxes

Apple’s Mail program will index the messages in your inbox, and then use this index to show you a new message or two. If this index is damaged, then it may not be properly updated so even though your Mac receives new messages, Mail is not displaying them. To fix this problem, select your inbox, and then choose “Rebuilt” from the Mailbox menu. This process may take a little time to complete, and you can see its progress by opening the Activity window, done in the Window menu.

Authenticate to Google

This long-standing bug may be oriented in Google’s security protection, which may be preventing your Mac as a device from accessing Gmail. This fix was outlined in the Apple Discussion boards:

1. Quit Mail
2. Open this page in your browser: https://www.google.com/accounts/DisplayUnlockCaptcha
3. Authenticate when prompted.
4. Relaunch Mail

Toggle Gmail account

This issue can sometimes be worked around by disabling and then re-enabling your Gmail account in Mail. While you can manage your Gmail account in the Internet Accounts system preferences, in this case you should go to Mail’s preferences and choose the Accounts section in there. Then select your Gmail account and uncheck the “Enable this account” checkbox, followed by checking it again. This action may spur Mail into properly interacting with Gmail again.

Remove the mail accounts cache

Mail will save account information in a local cache, that it uses for quick access to details like server configurations and the appropriate usernames to use. If damaged, this cache may affect how Mail attempts to connect to your Gmail account. Therefore, try removing it:

1. Quit Mail
2. Hold the Option key and select “Library” from the Go menu in the Finder
3. Go to the Caches folder that opens
4. Remove the file called “com.apple.mcc.accounts”
5. Re-launch Mail