Hi @22940184 ,
According to my research, the reason for this problem may be that Outlook is pointing to the wrong pst file or the data file is corrupted.
- Going into the control panel and editing the Outlook mail settings in the background, setting the original PST file as the default should solve the problem. To access these settings, go to Control Panel > Mail, select Data File and change the settings to point Outlook to the correct PST file.
- You can run the Inbox Repair Tool (scanpst.exe) to scan your Outlook data files and repair errors.Outlook 2016 and Outlook 2013: Repair Outlook Data Files (.pst and .ost)
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