I am using Outlook 2019 on one system and Outlook 2021 on another. Recently, I noticed that my PST files have grown quite large, and Outlook has started running more slowly. I have already deleted a lot of old emails and emptied the Deleted Items folder, but the PST file size has not reduced much. Can anyone please explain how to compact PST files in Outlook 2019 and 2021 properly without losing any data? Also, are there any best practices to keep the file size optimized and prevent Outlook from lagging again?