For a long time, I was facing problems like slowness and crashes in Outlook due to large PST files. After a lot of searching on the Internet, I used Softaken Compress PST Software, and the result was really amazing. This tool compresses PST files without data loss. Gives the option to remove old attachments or save them separately. The interface is quite simple, can be used even without technical knowledge. Works even without installing Outlook. If your Outlook file has become very large and you want to transfer it to another system, then this tool is very useful. I have used it myself, so I am confidently recommending it.