Trying to send/receive by "synchronising bin" prevents receiving or sending

“Synchronising Bin” usually means Outlook is trying to sync your mailbox’s Trash/Deleted Items folder and getting stuck. You shouldn’t need to restart the whole computer each time.

First, sign in to your email provider’s webmail and check whether you can send and receive there. Open the Bin/Trash folder too. If it contains a large backlog, recover anything you need before emptying it through webmail—emptying it may permanently delete those messages. Then fully close Outlook and reopen it. If Outlook stays running after you close its window, end Microsoft Outlook in Task Manager before reopening.

If webmail works but Outlook still gets stuck, and you’re using classic Outlook on Windows, test a new profile through Control Panel > Mail > Show Profiles > Add. Add your email account and choose Prompt for a profile to be used, so you can test without removing your existing setup.

If the new profile syncs normally, the old profile or its local sync data is likely the problem. Keep the old profile until you’ve checked for local-only folders, drafts, and unsent messages. If webmail also fails, focus on the provider’s service or mailbox storage limit rather than rebuilding Outlook.

I don’t know which type of account you are using (IMAP / POP3 or Exchange), but normally when Outlook is synchronizing for a long period it may be because the mailbox contains too many emails, and therefore it “has to re‑index all the messages,” which can delay the process. Another possible issue is the synchronization frequency. I once saw a case where someone had configured Outlook to synchronize every 5 minutes, but since there were many emails, the process entered an endless loop and the person never received new messages because each synchronization started before the previous one had finished.

Other possible causes to consider:

Very large folders (Deleted Items, Junk, Sent Items) slowing down synchronization.

Corrupted OST/PST file causing Outlook to hang.

Third‑party add‑ins interfering with send/receive.

IMAP accounts syncing all folders, including “Bin” (Trash), which can take a long time.

Unstable internet connection forcing Outlook to retry synchronization.

Antivirus or firewall blocking communication with the mail server.

Outdated Outlook version with known bugs.

Mail server changed the ports or configuration as certificantion

Try this:

Increase the synchronization interval to 15–30 minutes.

Empty or archive large folders.

Use the ScanPST tool to repair OST/PST files.

Temporarily disable add‑ins to test.

Update Outlook/Office to the latest version.

Test the account in another mail client to confirm if the issue is server‑side or Outlook‑related.