You can try PDS OST to PST converter software that recovery inaccessible OST file and conversion OST to PST file with full protection. It quickly again open each damaged file & folders from OST to PST  file with filter messages but after repairing vital damaged Offline OST file. This is a smooth way to fix emails and conversion emails & mailbox from OST2PST file, MSG,EML,HTML,MBOX. Software works on all supported versions-: 97 to 2016.

More Info-:  OST Converter