What is OST file (.ost) ? - Definition from Whatis.com

An OST file (.ost) is an offline folder file in Microsoft Outlook. Offline folders make it possible for the user to work offline and then to synchronize changes with the Exchange server the next time they connect. The ability to work offline is useful in environments with limited or unreliable connectivity.

Another type of file in Outlook is the PST file, which is simply stored on the client or a server other than the Exchange server. 

 

Related glossary terms: file allocation table (FAT) , cluster
This was last updated in October 2006
Editorial Director: Margaret Rouse

Premium Access

Register now for unlimited access to our premium content across our network of over 70 information Technology web sites.
By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy

Dig Deeper

Do you have something to add to this definition? Let us know.

Send your comments to techterms@whatis.com