Outlook takes a very long time to synchronize

Hi Bram,

This is April, I'll be happy to assist you. Sorry to hear that you're having issue with Outlook for Windows. Let me help you out.

Base on the description of the issue you provided, outlook is slow to synchronize messages at startup and when sending, despite fast hardware and only two mailboxes.

When Outlook is slow to sync, do you notice delays only at startup and sending or also during regular inbox refreshes?

If Outlook is syncing slowly even with powerful hardware and just two mailboxes, the slowdown is almost certainly due to configuration or network issues, not a performance limitation.

What to check when Outlook Sync is Slow:

1. Cached Exchange Mode
   • If this is turned off, Outlook keeps pulling everything from the server, which slows it down. Turn it on under: File > Account Settings > Account Settings > Change > Use Cached Exchange Mode
2. Mailbox Size & Sync Range
   • Very large mailboxes (even just two) can slow syncing. Set Outlook to sync only the last 12 months or less in: Account Settings > More Settings > Advanced > Cached Exchange Mode Settings
3. Add-ins Some add-ins (CRM tools, antivirus plugins) can slow Outlook. Try starting Outlook in Safe Mode to check.
4. Internet/Network Issues Even a powerful PC will lag if the connection is slow or unstable. Check for high latency, VPN issues or proxy delays.
5. Send/Receive Settings Outlook may be syncing too often or inefficiently. Adjust the schedule under: File > Options > Advanced > Send/Receive
6. Damaged OST/PST files A corrupted or oversized Outlook data file can cause delays. Rename the file, restart Outlook, and let it rebuild.
7. Antivirus or Firewall Scanning Security software scanning Outlook traffic can slow sync. Turn off mail scanning temporarily to test.

I hope this helps. If you need further assistance you can reply to this message.

Thank you,

April P.

Independent Advisor