You need to update Outlook to the latest version, I did that and it worked for me. It`s probably still possible to convert this file. Be careful as not to rename the extension to .pst files or any other files. This won`t change the file type. Only a special conversion program can change a file from one file type to another. So far this`s all the options I know of, but you should also look it up, there`s probably something more to it for sure. I'd also advise you to use this
https://revenuegrid.com/revenueinbox/s...dashboard/ tool when working with Outlook. Especially if you are in sales, it helps you a lot to automate your processes.