You Must Connect to Microsoft Exchange Once Before You Can Use Outlook Data File .Ost (Solved)
16You Must Connect to Microsoft Exchange Once Before You Can Use Outlook Data File .Ost (Solved)
Outlook may not synchronize at times if you’re using a Microsoft Exchange account if it was not set up properly.
Users trying to synchronize a Microsoft Exchange Server mailbox with an offline folder (.ost) file in Outlook will receive this error message:
Cannot start Microsoft Outlook. Cannot open the Outlook window. The set of folders cannot be opened. You must connect to Microsoft Exchange with the current profile before you can synchronize your folders with your Outlook data file (.ost)
Issues addressed in this tutorial:
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Outlook, when configured with Exchange server profile in Cached Exchange Mode, creates an OST or Offline Folder file. This OST file is encrypted with a unique MAPIEntryID GUID key, which is stored in the registry of your local system and Exchange server. Although Outlook OST file allows users to work even when the system is offline, it needs to authenticate the user profile by matching the MAPIEntryID GUID key with the server mailbox at least once to allow access to OST and Outlook profile.
This tutorial will apply for Microsoft Outlook 2021, 2019, 2013, and 2010 for both Windows (such as Dell, HP, Lenovo, Samsung, Toshiba, Acer, Asus) and macOS (MacBook Air, MacBook Pro, MacBook Mini) devices.