How to convert OLM to PST manually?

Follow the steps below to manually convert OLM to PST
Step 1: Setup an IMAP account using Gmail account
Open Gmail account then click on Gear icon on the right-hand side of Gmail account.
After that click on the Settings button.
On the Settings tab, you need to click on Forwarding and POP/IMAP tab.
Then check the IMAP Access status. If the status is disabled then enable it.
Once your IMAP account is successfully created, then you need to set up your Outlook for Mac with it. To do this, follow the steps given below:

Step 2: Add IMAP mail account to Outlook for Mac
First, open Outlook for Mac, then click on Menu ->Tools -> Accounts.
After that, click on Email. Here, enter an email address, password and other information which is asked. Then click on Add Account.
Once the above process complete then check the IMAP mail account.
After that, you need to create Gmail label, In order to perform synchronization between Outlook for Mac and IMAP account. To do this, follow the steps given below:

Step 3: Create a Label in Gmail
First, open your Gmail account. Then click on Gear icon on the right-hand side of Gmail account. Then, click on the Settings button.
Then on the Settings tab, click Labels and here, now click on Create New Label. And check Show in IMAP box is checked.
After this, go to your Mac Outlook and click on Send/Receive.
Now will move emails and other mailbox data from OLM file to the IMAP mailbox folder. To do this, follow the steps given below:

Step 4: Move or transferred emails from Mac Outlook to IMAP mailbox
Open Outlook for Mac, the right click on mailbox item which you want to transfer to Outlook for Windows.
Then select Move -> Copy to Folder.
After that type the name of your IMAP folder and click on Copy.
Then click on Send/Receive or refresh the folder on Gmail to update the mailbox. You need to do this when the above process completed.
Now your all the copied mailbox data have been synchronized to the IMAP mailbox folder.
After completion of above steps, now you will need to move all the emails or other mailbox data from the IMAP mailbox folder to Windows Outlook. For this, you will need to set up the very same IMAP mail account to the Windows Outlook. Then drag your IMAP mailbox folder data to your Windows Outlook Inbox Folder.

I hope this method will be helpful!
Paul Wilson