File Extension/OST
alphabetical list of extensions

File extension .OST

Description of the problem
If you have on your computer a .OST file that you cannot open, you are in exactly the same situation as thousands of other people who have similar problems with this or any other unknown file.

There may be several reasons why you cannot open the file with .OST extension. Directly on this website you can find a solution of the most common problem with the .OST file – that you do not have on your computer the appropriate program to open the file.
Solution
From the list below, select the appropriate program, install it and double click on the icon of a file that did not want to open - the problem with the .OST file extension should be solved. However, if this does not happen, go back to the website to learn about other possible causes of the error, which have been described at the bottom of the website.
Category
Misc Files
Developer
Microsoft
Popularity
StarStarStar
File name: Outlook Offline Folder File
Programs that will open this file:
Windows
Windows
Advanced Exchange Recovery Advanced Exchange Recovery
Convert OST to PST Convert OST to PST
Kernel for Exchange OST Recovery Kernel for Exchange OST Recovery
Outlook Outlook
Outlook Recovery Toolbox Outlook Recovery Toolbox
Remember!
The .OST file extension can correspond to several not related file formats. If there is more than one file format with the .OST extension, you will probably find most of them at this website. Remember that you need to download a program to support a particular file type. So first look through the entire contents of the website to select a program to support just the file you have.

Other possible reasons why your .OST file does not want to open

In addition to the problem described above, i.e. the lack of the appropriate application to support the .OST file, there may be several reasons that cause problems with opening and operation of the data format:

1. Incorrect version of the installed application

A quite common problem is the lack of application in the appropriate version. Even if you have an application, with the help of which you should open the .OST file, you may have a problem with it because of its version. Perhaps in previous versions the application has not yet supported the .OST file, so download the update and check again.

2. Incorrect .OST file association with the program

If you have already installed the appropriate application, and it is the correct version, the file may not open correctly, because the operating system does not have information that this program supports the file. So you need to "show" which program the computer should use. To do this:

  • Right-click the .OST file
  • Go to the "Open with" - then "Choose default program ..."
  • Locate the appropriate application
  • Click "OK"

3. The file is corrupt

It also happens that the file you want to open is corrupt and therefore there is no such possibility. In this situation, you should find its different version, or ask a person from whom you got, to send it again.