PSTCompactor - Professional Edition - Version 2.5.5 Reduces Microsoft Outlook PST file sizes up to 38% and simplify network PST file management. Compress & zip attachments, automate Compaction, etc. Can run at the server and manage PST's over the network. No Exchange dependency, no client software to install. 100% Outlook compatible - no proprietary file formats. Enforce corporate Email Policies. HOME USER, Small Biz and Enterpriseversions also available.