PST files which contain all the emails and items of user mailboxes have definite file sizes which is determined by the version of MS Outlook being used. If the file size exceeds the limit because of large volumes of emails email attachments and other mailbox items it may result in file corruption. Therefore to avert corruption in PST files their size must be within the predefined limits. The best way to reduce PST file size is to compress PST files along with their content. Compressing large PST files especially along with the attachments embedded with them help in reducing PST file size. Furthermore compressing PST files also facilitates better utilization of the unused spaces. In order to compress PST files users can opt for special software tools like Kernel for PST Compress and Compact. With the help of this utility users can not only compress PST files but also separate the attachments that are embedded with PST files and take up large disk space. There are four different options available for users when using this software. This tool can compress PST files including the attachments. Secondly it can also transfer all the attachments to a new PST file. This tool cal further remove all attachments from new PST file and save them in separate folders. Lastly there is an option for removing the attachments compressing them and then saving in a separate folder. Kernel for PST Compress and Compact is also capable of compressing multiple PST files and compact them in a single conversion cycle. A maximum of 2147483648 PST files can be compressed at a time indicating least disk space consumption. After compress PST process separate folders are created where the compressed files are saved. Data integrity is preserved even after compression and compaction of the files. Therefore a major cause of corruption can be resolved with the compress PST process.