Ans: Microsoft outlook is a very popular program from Microsoft office and it used as Personal Information manager worldwide. MS outlook stored its data in PST (personal folder file). Over the time PST file become very large and after years of usage it becomes huge. Huge PST file start to develop many more complications despite the robust file format (PST). These complications are as follows:

• Slow performance of MS outlook as it needs to parse huge PST file.
• Chances of becoming corrupt due to many reasons which can be a small disk failure or use of any malfunctioning software or virus.

Now you must have understand that there a urgent need to compress the size of MS outlook PST file as critical mails and other information is stored in it and lose of data is painful as it costs a lot of money and time. Slow performance has a very low weight-age as compare to previous issue but still it exists. Now we come to the point as how to reduce the size of PST file. As all we know that most e-mail's size usually has 80% data as attachments rest 20% is email content. There are two methods by which we can compress the size of huge PST file.

• Activate the compression scheme built in MS Outlook PST file. This is very useful in general and easy to deploy but for that one must have some knowledge of internals of PST file or MS Outlook. But this might be not as helpful as all attachments will remain inside of PST file.
• Open MS Outlook and manually remove all your attachments from mails to a separate folder to your disk and remove them from your mails. You have to do this for all your emails and all objects of Ms Outlook where attachments can be embedded. Alternatively you can remove them compress them by using zip software and then re-attach them. After completing this process again perform the first method.

The second method is more effective and useful as it can reduce the size of your PST file up to 80% and by combining both methods you can reduce the size of PST file up to 90%. It sounds impossible but it is.

You can use this simple method to reduce the size of the PST file:

1. Click Start, point to Settings, and then click Control Panel.
2. Double-click Mail.
3. Click Data Files.
4. Click the .pst file that you want to compress, and then click Settings.
5. Click Compact Now.