How to convert an ost file to pst file in order to open it in an Outlook profile.
Remove a password from an Outlook *.pst File
How to remove a password from a Personal Folder (.pst) file in Microsoft Outlook.
Repair a Large Outlook Personal Folders File (over 2GB)
Microsoft Outlook limits the size of older Personal Folders .pst files and offline folders .ost files to 2GB. If a new or changed item increases the size over than limit, you will not be able to use the .pst or .ost file. Even if you delete items from the server mailbox, the .ost file will not synchronize.
How to repair a damaged Outlook Personal Folders file (pst)
How to repair a damaged or corrupted Microsoft Outlook pst file, personal folder or data file and recover your Outlook email, calendar and contacts. In many cases you can repair your data file using the free Inbox repair tool (scanpst) that Microsoft includes with the Outlook installation.