How to Compact a Large PST File in Different Versions of Outlook ?

Microsoft Outlook is the most widely used email application program that stores and saves all email objects for example messages, calenders, contacts etc in PST file. Compacting or compressing Outlook PST file is always useful
and recommended because regular use of MS-Outlook increases the size of PST file which makes Outlook slow and messy. There are several benefits of compacting a PST file which primarily includes the reduction in the size of a large .pst file. This prevents the .pst file from corruption and improves the performance of Outlook.

For compacting PST file, Outlook has the inbuilt feature as “Compact Now” which reduces the size of PST file. For .pst compaction, a file must fulfill following requirements :

• A file should be 16 KB or larger than this.
• A file must have the 16 KB of free space, since the last time it has been compacted.

In earlier versions of Outlook the .pst file size was limited to only 2 GB. However in later versions like Outlook 2003 and 2007, the size limit has been increased upto 20 GB. In Outlook 2010, it is extended to 50 GB. Although, the size limit has been increased, but still it is a good practice to compact the .pst file on a regular basis.

Compact PST file in different versions of Outlook :

Outlook 2003 to 2007

1.Open MS Outlook program by clicking the icon or the File menu in the Start menu.

2.Click "File" from the standard toolbar.

3.Click "Data File Management" from the drop-down menu.

4.Click twice "Personal Folders" to highlight.

5.Look for "Settings" and click that button.

6.Select the "Compact Now" button from the General tab box.

7.Compact personal folder .pst file by clicking "OK" and close the box.


Outlook 2002 and earlier versions

1.Open Outlook and click on "View" in the standard Toolbar.

2.Click "Folder List" from the drop-down menu.

3.Right click on a Personal Folders file.

4.Choose "Properties for Personal Folders" to compress.

5.Use the mouse on the "Advanced" Open the General tab.

6.Select "Compact Now".

7.Select the OK button.

Generally, the above mentioned steps work well in normal situations. But sometimes the PST file gets very large or due to some other Outlook error, you are unable to compact .pst with “Compact Now” option. In such a situation, you can use a third party Compact PST Software to compress the oversized PST file by extracting attachments from messages. Also such software is specially helpful when there is a requirement of more free space.