When you use Microsoft Outlook to open a corrupt or orphaned offline folder (OST) file, or synchronize it with the Exchange server, you will encounter various error messages, which may be a bit confusing to you. Therefore, here we will try to list all possible errors, sorted according to their occurring frequency. For each error, we will describe its symptom, explain its precise reason and give out the solution, so that you can understand them better. Below we will use ‘filename.ost’ to express your erroneous Exchange OST file name.

Moreover, when using offline folder (OST) file with Microsoft Exchange server, you may also encounter the following problems frequently, which can be solved by DataNumen Exchange Recovery easily.