"Create Diagnostics Report" not generating (or not generating in right location)? For some reason opt + right click on wifi (top right of screen), then selecting &quot;Create Diagnostics Report&quot; doesn't generate said report.
I see the following pop up (which I believe is normal):
But then after clicking &quot;OK&quot;, I have seen nothing for 1h 15m. I have been waiting for a finder window to appear. I have also manually checked in /tmp, ~/Downloads, and ~/Documents, but cannot see the report.

I cannot work out why this would be. Perhaps I have changed to location the report would write to? Is it possible to run a diagnostics report via terminal (and perhaps specify where it should be written to?)
I just ran this on my older iMac running High Sierra. It ran to completion in about 10 minutes. It wrote the output to the tmp directory but probably not the tmp directory you checked. On my machine, it wrote the output to /private/var/tmp. The folder 'private' won't show up using Finder unless you 'show hidden items'. This requires hitting the command-shift-dot keys at the same time. Then the Finder will display the 'private' folder. So from / you can see the private folder. Other folders on that level are Applications, Library, and Users among others.