Outlook pst Compression

The steps to follow are:

1. Find your largest mail

a. Go to Tools>Find>Advanced Find
b. Pick "More Choices", change the size field to is "Greater than", put in 5000 (Kb).
c. Sort the files it finds by size

2. Delete unneeded mail from the search results and empty your deleted items.

3. Compact the folder

a. Right click on the folder store itself (Personal Folders, or
Archive Folders, or some such).

b. Go to Properties, Advanced, and click "Compact Now".

This will decrease the file size significantly.