I recently installed Office 2021 Plus (I had Office 365 license that expired). Prior to the installation of Office 2021, I had offline email messages in Outlook 365 that I could access without signing in to the Exchange account with a .ost file. I still have cached exchange mode checked after switching from Office 365 to Office 2021. After installation of Office 2021, I can no longer access the offline email messages in Outlook 2021 with the .ost file from Outlook 365. See below the error message that I received when I clicked on the Exchange Account trying to expand the email folders.
I don't need to synch with the Microsoft Exchange to retrieve new/updated emails, but I do need to retrieve certain emails that are in the .ost file. Based on the information at Microsoft Support, there are no .pst files associated with the Outlook 365, only .ost file.
I have tried repairing the both .ost files associated with my Microsoft Exchange and Yahoo account data files (.ost) using the ScanPST.exe and Outlook still could not be launched even after both .ost files were repaired. Disabling all add-ins didn't help either.
Why was I able to read/access the offline messages in Outlook 365 but could no longer see them? How can I retrieve the the offline email messages that are in the .ost file without signing in to the Exchange account just like when I was in Outlook 365?
Do you guys have any suggestions? Greatly appreciate your insights.