0x8004103b

The error code 0x8004103b in Outlook on Windows 10 indicates a synchronization issue between your local OST file and the Exchange server. This error typically occurs when Outlook cannot synchronize the offline storage table (OST) with the server, often due to an unstable internet connection, a corrupted OST file, or a problem with the Exchange server. To resolve the error, you can repair the OST file using the ScanPST.exe tool, which scans and fixes corruption in the file. Other solutions include checking your internet connection, recreating the Outlook profile, or disabling add-ins that may interfere with synchronization.