IMAP send recieve problem

Question

the send/receive on an imap email account, within MS365 has got stuck in a loop. Stays stuck in the send receive synchronisation. Will not update the receive folder

Answer 1

First check the mailbox in its provider’s webmail, then apply the matching Outlook recovery steps below for Windows or macOS and New or Classic Outlook.

1. Determine whether Outlook or the mailbox is stuck

1. Sign in to the affected mailbox through the email provider’s webmail.
2. Send a test message to the account from another address.
3. Check whether it arrives in webmail:
   • It arrives in webmail: the IMAP server is receiving mail, so troubleshoot the Outlook client below.
   • It does not arrive: contact the organization or provider hosting the IMAP mailbox. Reconfiguring Outlook will not resolve a server-side delivery problem.
4. Inspect Outbox and Drafts for an old or oversized message. In New Outlook, Microsoft notes that one oversized message can block messages after it; start with the oldest Outbox item and remove or reduce large attachments.^1^

Before removing an account or profile, confirm that mailbox content is visible in webmail and back up any local-only folders, unsent drafts, or other items that have not synchronized.

2. Classic Outlook for Windows

Adjust the IMAP send/receive group first:

1. Open Send/Receive → Send/Receive Groups → Define Send/Receive Groups.
2. Select the affected account and choose Edit.
3. Clear Get folder unread count for subscribed folders.
4. Under received mail items, select Inbox only.
5. Save the changes and restart Outlook.

This configuration has been used specifically for Classic Outlook IMAP folder synchronization that does not complete.^2^

If it remains stuck, create a separate profile rather than immediately deleting the existing one:

1. Close Outlook.
2. Open Control Panel → Mail → Show Profiles.
3. Select Add, enter a new profile name, and configure the IMAP account.
4. Select Prompt for a profile to be used, then start Outlook with the new profile.
5. Allow the initial synchronization to finish and test incoming mail.

Do not remove the original profile until the new one works and all required local data is accounted for. Microsoft identifies outdated software and corrupted profiles as common causes of send/receive failures.^3^

3. New Outlook for Windows

New Outlook has no configurable send/receive interval and is intended to synchronize automatically. The View → Sync command can initiate a manual sync, but generic third-party IMAP accounts do not have the same manual-sync capability.^1^

If webmail updates but New Outlook does not:

1. Back up any unsynchronized or local-only items.
2. Open Settings → Accounts → Your accounts.
3. Select the affected account, then Manage → Remove.
4. Restart New Outlook and add the account again.
5. Confirm that new messages now appear without restarting Outlook.^4^

If available, temporarily test the same account in Classic Outlook. If Classic Outlook works while New Outlook repeatedly stops receiving, use Classic Outlook as a temporary workaround and escalate the New Outlook issue.^5^

4. Outlook for Mac

A closely matching Mac IMAP sync-loop case was resolved by installing a fresh Outlook copy, granting Full Disk Access, re-adding the account, and clearing Drafts.^6^ Treat clearing Drafts as a secondary Mac-specific check, not a general IMAP requirement.

1. Verify server content and back up local-only items.
2. Install a fresh Outlook copy from Microsoft’s Office for Mac update channel.
3. Open System Settings → Privacy & Security → Full Disk Access and enable Outlook.
4. Re-add the IMAP account and let synchronization complete.
5. Move or delete problematic Drafts only after preserving anything needed.

Privacy warning: Full Disk Access permits Outlook broad access to protected files. If it does not fix the issue, disable that permission again under Privacy & Security → Full Disk Access.

Escalation

If this is a third-party IMAP mailbox, provide its host with the synchronization timestamp and any exact error shown in Outlook. If the mailbox is actually hosted in Microsoft 365/Exchange Online, an administrator can check Exchange Online service health and run the Outlook User Connectivity diagnostic; that diagnostic requires a Microsoft 365 administrator account.^3^

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References

1. [New Outlook](https://support.microsoft.com/outlook/i-can-t-send-or-receive-messages-in-outlook#check-if-you-are-experiencing-sync-issues)
2. Outlook folders synching not completing - Microsoft Q&A
3. Fix Outlook connection problems for Microsoft 365 account
4. How to get New Outlook to sync often - Microsoft Q&A
5. New Outlook does not sync new emails in O365 Business. - Microsoft Q&A
6. Outlook 365 for Mac sync loop - Microsoft Q&A