Users may encounter issues opening OST files in different versions of Outlook due to various reasons. Common causes include file corruption, which can occur during synchronization or software crashes. Incompatible Outlook versions can also prevent access, as OST files are version-specific. Insufficient permissions or user profiles can lead to access problems. Additionally, if Outlook is improperly configured, it may not recognize the OST file. For more info- https://www.emailsguru.com/blog/how-to-open-ost-file-in-outlook/