Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Hi Michael,
Sorry about all the inconvenience caused by this issue, we totally understand your frustration on this issue.
I've go through this thread and would like to provide my help here.
I've noticed during the troubleshooting with Qing, you focus on the permission level of the MAU's download folder. But as you completely re-installed MACOS Mojave 10.14.5 with no avail, I think it's the time for us to look at this issue from a different angel. I've searched for the similar issue like yours, some of them indicate issue was resolved after adding the DNS on their Mac. If it's convenient for you, please check if the following method could help in your scenario:
How to Use OpenDNS or Google DNS on Your Mac
Disclaimer: Microsoft provides no assurances and/or warranties, implied or otherwise, and is not responsible for the information you receive from the third-party linked sites or any support related to technology.
Personally, I don't think this issue is related with the WiFi/Wired network, as all your other Mac's MAU is working as expected, this indicates there is nothing in this network will prevent the MAU to download the updates. So, I think we need to focus on the difference between this issued Mac and your other Macs (non-hardware). For instance, have you ever used proxy settings on this Mac?
Also, could you go to ~/Library/Logs/Microsoft, see if there is a log file named as autoupdate.log. If so, please provide us with this log, it might be helpful for the further troubleshooting on this issue.
Please let us know the update, we greatly appreciate your time and effort here.
Regards,
Alex Chen