Using New Outlook on Windows for professional communication and productivity
So new ones show but older ones they were opened and edited are not showing?
Do you have more than one account in new Outlook? The insert list shows files saved to OneDrive for the account the message is from. Unlike classic Outlook, the file list is not per-computer, its by account. And it is onl files in OneDrive - not recently used files anywhere on the computer.
My list looks current but I have not created new files the last day or two - and I save most files in one of my 3 OneDrives.