What is the purpose of outlook.ost on a laptop?

[M Skabialka]

What is the purpose of outlook.ost on a laptop? One of our folks has a 3 GB
outlook.ost file but as far as I know his laptop was never set up for
offline access to his email (I set up the laptop) and he has never used
Outlook when not connected to the internet somehow. The date on it is
today.

 

[Vanguard]

What is the purpose of outlook.ost on a laptop? One of our folks has a 3
GB outlook.ost file but as far as I know his laptop was never set up for
offline access to his email (I set up the laptop) and he has never used
Outlook when not connected to the internet somehow. The date on it is
today.

Is the user connecting to an Exchange server? If so, is cached Exchange
mode enabled in their Outlook?

 

[Sue Mosher [MVP-Outlook]]

It's most likely an offline copy of their Exchange mailbox, created by the default settings (Cached Exchange mode) in Outlook 2003. Having such an offline copy means that if the network is not available, the user will be able to continue working in Outlook without even blinking.

--
Sue Mosher, Outlook MVP
Author of Configuring Microsoft Outlook 2003

and Microsoft Outlook Programming - Jumpstart for
Administrators, Power Users, and Developers