If you want your Outlook to perform fast and reliable, watch your mailbox and other storage sizes carefully. Separate your large Outlook storage into several parts of smaller size and you will notice the difference: smaller storage work faster and better. This utility creates new PST storage of smaller size, doesn't make any changes to existing ones and retains all your data intact. Thus, if you don't like the result, you can always revert back to you original unmodified storage. In addition to partitioning Outlook storage by size, partitioning by year is also available.