The user who are facing problem in accessing the OST data in Outlook then you need to convert them into PST format which can be simply imported into Outlook email client the user can make use of Softaken OST to PST Converter application which can be a game changer for the data user and give accurate result for the OST to PST Conversion.
Go to C Drive > Program File > Microsoft Office > Office 2007. After doing this you will see the PST files. Right click on it and go to the Properties and then select the Compatibility tab. Click on it to clear down all the Compatibility Mode Check Box. After doing so, click on Apply and then press OK. Restart the computer and your problem is sorted out. If you are still looking for any other solution, then you can try OST to PST conversion software. Try it from here: https://itknowledgeexchange.techtarget.com/itanswers/ost-file-problem/
The OST to PST Converter for Mac this application Migrate Outlook OST file to Outlook PST Database format. This software recover OST file and corrupt OST file. It also a simple and fast conversion. You can try this application to help with easy conversion and Migrate OST file to PST file format. Download the free trial version.