How to Increase PST Size limit? To Increase PST size limit (2GB to 20GB) or to upgrade Outlook PST files, you must try our PST file conversion utility. Using this well-performed PST Upgrade Tool user can upgrade or convert ANSI to Unicode and increase Outlook mailbox size limit. Software is feasible with all Windows version like Win 98 to Win7. SysTools for PST upgrade is a simple way to upgrade your Outlook environment and it gives you easy and graphical-user-interface which can easily convert ANSI PST (MS Outlook 2000/2002/XP) to Unicode PST (MS Outlook 2003/2007) and it also be able to convert Unicode PST (MS Outlook 2003/2007) to ANSI PST. Upgrade PST utility has ability to convert all the mail folders like Inbox, Outbox, Sent Items, Drafts, Deleted Items and Contacts etc. PST upgrade tool is the best solution for PST file conversion. With the help of this utility you can successfully convert ANSI to Unicode but user can't be able to convert corrupt PST file (lowest version of Outlook), if size limit exceeds than 2GB. PST upgrade program is widely used for upgrade and maintain Microsoft Outlook with all of its email metadata information (to, from, cc, bcc, sent/receive date and time, attachment etc). Demo version will allow users to upgrade only first 3 folders of Microsoft Outlook. Wants to convert unlimited PST file, get full version of this utility at acceptable prices. Personal license is available in the market at just $49.