More to the point, I cannot even send a fax. Its not a show stopper as I can still manually open the fax folder to see what I want. Tried setting permissions as per the link you quoted, but it made no difference. Let me know if that link helps or not, if not we'll try something else. (My opinion on this is, they don't know either) This is a lame duck issue with MS and I'm sure many users have noticed this lack of actual help from MS. MS's help system has been gutted out of Windows 10 and replaced with online links to landing pages that do not offer an real answers, only promotions of the Windows 10 system and links to common questions. The reason some of the questions folks are asking go unanswered is because no one really knows how to answer it yet. I know how frustrating it is to ask for help and not receive any kind of reply.

Perhaps someone else who has used the new Fax app can provide a better answer, but I figured I'd try and offer some kind of advice. I think something similar is going on with the Fax and Scan app as well. Example is the inbox showing 300 plus emails and after setting up the account and manually syncing the account produced only a handful of emails, even after telling the app to download all mail from anytime. I ran across a similar problem with the Mail app, where the app simply will not sync past messages from 3rd party email providers. Side note, apparently many of the newer 'universal apps' are not very backwards compatible with previous versions of the modern apps counterparts under Windows 7. Check the folders permissions under the folders properties and make sure your user account (user PCname/user) is the owner and has full access. It could be your local user account does not have access to the folder where the data you want to access is stored. The info is for Windows 7 so the instructions might be a bit different but it does mention taking ownership of specific folders and reveals the location of where fax data (system side) is saved to.

The topic is here: How to transfer fax and scan data from one user profile to another. Below is the only link I could find that may have a solution for you. However I looked around on the internet to see if anyone has posted about this issue or one similar to it. I have not used the fax and scan feature in Windows 10 yet, no reason to us it. Hello keithjr and welcome to Windows 10 forums.

Win 10 fax and scan