Why are my folders not migrating from G Suite or Gmail?
Within Google's settings, users have the ability to turn IMAP access on or off for specific folders. If you notice that a folder is not migrated from your G Suite/Gmail account, it is important to make sure that IMAP access is enabled for that folder.
To turn IMAP access on or off for a folder:
Sign in to your Gmail account.
Click on the gear icon at the top right of the Gmail window.
Click on Settings.
Go to the Labels tab.
Check Show in IMAP for All Mail, and for any other label you want to include in an IMAP client or migrate.
For more information from Google about IMAP access for folders, click here.