Fix: 0x80040600 Unknown Error – Outlook

When you attempt to send/receive emails in Microsoft Outlook, you may receive an Unknown Error.

Task “” reported error (0x80040600) : ‘Unknown Error 0x80040600’

Sometimes, you can produce this error alongside an OST / PST file error, but it may not appear always. The error is likely related to a corrupted or inaccessible OST / PST file that is likely hosted on a network drive.

1. Close Outlook and re-open again. See if you can send/receive email without errors.

2. If not, reboot your Windows machines and open Outlook and try again.

If this does not work, follow the instructions outlined by Microsoft Support to repair your Outlook inbox or OST / PST file.