Start the Mail app on your Mac, right-click the Google inbox and select Get Account Info. Even with Mail, it is worth limiting the number of messages it downloads. Mail does seem to cope with high volumes of email messages, even though it takes a long time, but not all email clients do so well. Perform a clean install of macOS or buy a new Mac and all those thousands of emails will be synced by Mail, and it takes a long time. Some people have as many as 50,000 emails going back 10 years or more.

After adding your account, Mail will download every email in your Gmail account, ever, and that could be a lot. Where you might run into difficulties is when initially setting up Gmail in the Mail app. Gmail handles them without any problems in a browser, but if you use the Mail app on your Mac or some other email client then there is the potential for problems to arise. Maybe even tens of thousands of messages.

If you are a heavy user of Google Mail and have had your account for a long time, you could have a very large number of email messages stored in your account. Do you access Google Mail using the Mail app on your Apple Mac? It could be downloading tens of thousands of email messages that take forever to sync.

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