Sync limits for accounts
- Android Gmail app
- Google Sync clients (using the Microsoft® Exchange ActiveSync® protocol)
- G Suite Sync for Microsoft Outlook® clients
- Gmail Offline app for Google Chrome
Don't perform migrations or bulk operations using sync clients
- Avoid large copy/paste or drag/drop operations in your email client.
- If you're migrating, use a supported migration option and avoid using drag/drop or copy/paste in G Suite Sync for Microsoft Outlook® to upload messages. Try using the integrated import function in G Suite Sync. (This is particularly important if you've exceeded the upload bandwidth limit via sync.)
- Avoid manually resyncing the client, particularly when using G Suite Sync. This can unnecessarily download the entire mailbox again, rather then syncing only the last changes.
- For G Suite Sync, try reducing your local mailbox size.
Prevent continuous retries
- Look for messages stuck in the Outbox of any of your sync clients. Messages that are rejected by Gmail due to blocked attachments or attachment size may remain in the Outbox and repeatedly fail to be uploaded, using up bandwidth continuously.
- Some network issues may cause clients to fail when uploading messages, making them retry repeatedly. Make sure your network connection is stable, for example by switching between mobile data and WiFi.
- Drafts containing attachments can consume large amounts of bandwidth as they get updated when the draft is saved. Avoid unnecessary and redundant drafts.
Manage your sync clients
Having multiple clients means every message gets downloaded multiple times, proportionally increasing bandwidth consumption. Remove or disable unused sync clients and quit clients when not in use. Changes made on one client or the web interface sync to all clients, so avoid making large changes if you have multiple sync clients, or decrease the amount of clients in use.
Check for unknown/unwanted sync clients
In some cases, a user or admin may have set up a sync client and stopped using it without disabling it. Try either of the following to check sync clients:
Navigate to the Google accounts authorizations page and revoke any unwanted items under Connected Sites, Apps, and Services and Application-specific passwords (if applicable).
Change the G Suite password to make sure any sync clients set up using that password can't access the account anymore; then enable desired clients one by one a few hours apart to pinpoint any offending client.
Use an alternative method
You can use the web interface or IMAP while you investigate sync issues, as a workaround while sync is locked out, or permanently in order to minimize sync usage.