Hi,Haunti41

The OST file format is very complex. It starts with a file header containing the meta information of the whole file, followed by several parts containing the actual data. You can find more detailed information about the OST file format by searching on Google with the keyword “OST file format”. If the file header containing the meta information is corrupt, or any follow-up parts are damaged or corrupted, then you will not be able to access the file correctly with Outlook. In such a case, the first step is to try to use the built-in repair or recovery function in Exchange and Outlook, to see if it can repair or recover corrupted OST file for you. If not, then you need to resort to a third-party Exchange recovery tool to scan the corrupted file, retrieve all recoverable data for you, and output a PST file which can be opened directly by Outlook. It is also possible to find a data recovery expert or company to do the task, but in most of the cases, they will also use a third-party tool to do the recovery for you.

The main difference between using the software by yourself and by a third-party service company is: (1) The company is familiar with the data recovery industry so he knows which software is the best one. While you need to search and compare the software online by yourself, which is time-consuming. (2) The company purchases the software for multiple usages, while you purchase the software for one-time usage only. So normally the service fee may be cheaper than the license fee for the software. (3) DIY will keep your data confidential while do the recovery via a company may cause data breach.

If you want to perform a DIY recovery, then you can try a third-party Exchange recovery tool to repair you ost file and convert ost file to pst file. Normally this tool provides a free trial so you can try first to see if it works before purchase it.

Hope this will help. Good Luck!