where a PDF is created in Adobe Acrobat 64-bit. Once created, it will open up and can be saved as a new document, which should then count as a recent document. In the Win11 File Explorer, it shows up in the recent section without issue, but Outlook won't populate it within its own recent section when trying to attach to an email. If we re-open the document, then it does, but that has not been the requirement before.

see reddit page: https://www.reddit.com/r/Outlook/comments/1mumzuy/recent_files_in_local_outlook_not_actually/