“Outlook OST file is not an Offline folder” – Did you get this error message when starting MS Outlook?
There are many users who receive above error messages, but what are the reasons behind these types of error messages. Read the below section of this blog I will describe the all responsible reasons for this message and how to resolve this type of error.
As we know OST file is created when Outlook is used in conjunction of Microsoft Exchange Server. Sometimes synchronization between Exchange Server and MS Outlook gets fail, it will make OST file inaccessible. When OST file gets corrupted, then MS Outlook fails to recognize it. In this time, if any user tries to access their OST file it displays a message like; “Cannot open your default email folders. The file *.ost file is not an offline folder file.”
To resolve this error like Outlook OST file is not an Offline folder file, you should do as follow:
To access OST file. Firstly, you will repair your corrupted OST file using scanost.exe tool else you need to convert corrupted OST file to Outlook PST file.
Otherwise, you can recreate OST file in Outlook to solve different issues related to OST file. Learn more about how to recreate OST file in Outlook account.
If the problem still persists, then try the revolutionary recovery procedure of Best OST to PST Conversion Tool to convert OST file into PST file. This solution resolves any errors related to OST file. Tool will keep care about each part of your OST mail while transfer data from OST to PST. One bonus feature using this software is that it does not require Microsoft Outlook and Exchange Server connectivity to access OST file.
Transfer Data from OST to PST 