To convert OLM to PST manually, you can use an IMAP email account like Gmail. First, configure your Gmail account in Outlook for Mac, then move all OLM mailbox items to the IMAP folders. After syncing, set up the same Gmail account in Windows Outlook and move the synced data to a new PST file. While this works, it's time-consuming and not ideal for large or complex mailboxes. For a more efficient and secure method, try the MSOutlookHelp OLM Converter, which ensures smooth and accurate conversion of OLM files to PST without data loss.