how to trim outlook.ost when it gets big

[Jake Lee]

Hi,

My outlook.ost grows to more than 600MB and this file is configured as
default for my exchange account.
I created a separate personal folder to house some of the mails and folder
structure in outlook.ost and also created a pst file for this.
I moved some mails and folders to this new personal folder and saw the
changing size.
But I didn't see any changes in the size of that outlook.ost file. It
remains the same even there are just a couple of plain emails without any
attachments.
Anyone knows how to solve this? Thanks a lot...

J-

 

[Venkat Srinivasan.R [ MSFT ]]

This posting is provided "AS IS" with no warranties, and confers no rights

Hi Jakee,

I found the following KB article that talks about the same issue.

E-Mail in an .OST file are Larger than in a .PST file: (The difference is
as large as 60% !!! Read the link below for more info )
===============================================
http://support.microsoft.com/default.aspx?kbid=817957&product=out2003

Regards,
Venkat.

 

[Brian Tillman]

My outlook.ost grows to more than 600MB and this file is configured as
default for my exchange account.

What version of Outlook? Have you compacted your OST? For all versions of
Outlook supporting OSTs, 600M is not too large. At minimum, your OST can be
twice that big.

I created a separate personal folder to house some of the mails and
folder structure in outlook.ost and also created a pst file for this.

Well, "Personal Folders file" and "PST" are synonymous, so "creating a
separate personal folder" and "creating a PST" mean exactly the same thing.

I moved some mails and folders to this new personal folder and saw the
changing size.
But I didn't see any changes in the size of that outlook.ost file. It
remains the same even there are just a couple of plain emails without
any attachments.

For OL 2002/2003, the steps you use are: right-click "Outlook Today", Select
Properties, click Advanced. Select the Advanced tab, then click Offline
Folder File Settings and Compact Now.

 

[Jake Lee]

1. I am using Outlook 2003; have not compacted it yet...maybe I should ask
what actually that ost file contains - since there are only 3-4 emails and
the rest got moved to a personal folder stored in a separate data file
(pst).
2. after compacting the file, it becomes much smaller...down to 85MB now...

 

[Brian Tillman]

1. I am using Outlook 2003; have not compacted it yet...maybe I
should ask what actually that ost file contains - since there are
only 3-4 emails and the rest got moved to a personal folder stored in
a separate data file (pst).

The OST is a mirror of the Exchange server mailbox. Its purpose is twofold:
it allows you to work offline while appearing to be connected to the
Exchange server, with access to everything that was on the server at the
moment you went offline. It also allows improved performance by creating a
local copy of the items in the Exchaneg mailbox. In cached mode, Outlook
doesn't present new items to you until they've been downloaded from the
server and if you access an item, you access the local copy, thereby
increasing apparent performance. Or at least that's the way our Exchange
admins explained it.