When Microsoft releasing of MS Office higher versions (2003 & 2007), then all users of Outlook 2000/2002 are looking for a software which can successfully convert ANSI PST to Unicode PST. There are many advantage of using MS Outlook 2003/2007 over MS Outlook 2000 as the old versions has oversize limit of .pst file 2 GB and the Unicode PST has oversize limit of 20 GB. Now if you are worrying about file corruption due to exceeding oversize limits of your mailbox and want to upgrade your mailbox to a higher version of MS Outlook then SysTools PST upgrade software is an easy and commanding way out for you. You can convert Outlook 2000/2002 mailboxes to Outlook 2003/2007 using SysTools Convert Outlook 2000 to 2003 Tool. The most attractive part of this software can also downgrade the UNICODE PST to ANSI PST and vise versa. Suppose you have created your PST file in Microsoft Outlook 2003 & 2007 and you want to open it in MS Outlook 2002 and in its older versions then MS Outlook 2000/2002 will not allow you to open the PST file and results in error as "Properties for this information service must be defined prior to use". To open the Unicode PST files in Outlook 2000/2002, you need to downgrade or convert the Unicode PST to ANSI PST file using PST UPGRADE software. While converting Outlook 2000 to Outlook 2003 you must have Microsoft Outlook 2003 & 2007 installed with a valid configured profile. Open your Outlook 2000 PST files in Outlook 2003 with Outlook 2000 to Outlook 2003 converter Software. Outlook PST Upgrade software runs smoothly in Windows XP/2000/2003 and Vista Operating System. PST Upgrade software will help you to convert all data from your mailbox folders, calendars, to-do-list and etc. SysTools Software always a true value for your money. Before you decide to buy this software for all its key features you can go for the trial version and then purchase the full version at just $49 for personal and $129 for business license.