Get Rid of OST File Error by Knowing the Corruption Reason

Sandeep Saxena
Sandeep Saxena linkedin | Updated On - December 15, 2022 |

Read time 4 minutes

An OST file is one of the most prominent features of MS Outlook that facilitates its user to work in an offline mode when Exchange Server gets down. The exclusive feature of OST file is to synchronize with the Exchange Server, which turns effective for the Outlook users in order to have an effectual communication. However, the real difficulty starts when OST files get corrupt and results in the loss of data. In fact, every time any OST file error take place the data saved in the OST file in such situations turns inaccessible. To effectively deal with such conditions, user would require to export OST to PST, and then access it in MS Outlook.

To understand the situation in proper manner, let us consider a situation. When you attempt to synchronize the OST file with the server, surprisingly you find that the MS Exchange Server no longer exists. And, the moment you made an attempt to access the OST file, you get encountered with an error message as shown below:

“Cannot open OST file. You must access Exchange at least once to use the OST file.”

Now, once this error message appears on the screen, the data, such as, calendar entries, contacts, even e-mails, and other items gets inaccessible. The problem turns trickier when you keep on facing the same error message again and again when you try to access the OST file.

Reason of file corruption:

The real cause of facing such an error message is a user making attempt to open an orphaned OST file.


Now, the most ideal way to tackle with such OST file error is performing an OST file conversion. There are two free method to convert OST file to PST. One is manual and other is a third party tool. To manually convert OST file to PST format, follow the instructions given below:

  • Start on Outlook. Log in to your Exchange email server, so that you could view the contents of your OST file.
  • In Outlook, click “File,” and after that click on “Import and Export.”
  • Get on “Export to a file” and “Next
  • Click “Personal Folder File (.PST)” and “Next.”
  • Click “Personal Folders” at the top of the list, and then click “Include subfolders.”

Note: However, you got to take care while selecting and clicking the appropriate categories in the list, so that you could export only certain data such as your contacts. Click “Next.”

  • Click on the “Browse” button. Navigate down to a folder on your hard drive where you desire to store your PST file.
  • Enter a file name and after that press “Enter.”
  • Choose how you wish to manage the possible duplicate items and click “Finish.”

The manual process can be very time-consuming and therefore to systematically to fix the error, as a user you need to opt for an effective third-party OST conversion software. By making the right usage of OST conversion tool like Kernel for OST to PST Converter tool, one can easily convert all the OST data, be it email, attachments, notes, or any anything into a PST format. The utility has been programmed in such a manner that it can easily restore attachments along with the images that are attached to messages and are included in HTML bodies. Along with that, the software even provides ‘Find Message’ option that further makes the entire operation of searching and finding the emails lot easier. Moreover, the tool is available in trial version and so you can give a try and evaluate its performance.


The given error in the article is the most common OST error that many users face with their Exchange accounts. No manual recovery solution like ScanPST can recover OST files. The user will need to delete the account and add it again in Outlook. But, if you use OST conversion software, then you can restore OST files without affecting the account in Outlook. You can restore contents in PST files and import it to Outlook application ,and access simultaneously.

View the complete process of OST Conversion- Video

Kernel for OST to PST