When attempting to pin a folder to the quick access toolbar, which I have enabled in DO, I get the following error code:
"This file does not have an app associated with it for performing this action. Please install an app or, if one is already installed, create an association in the Default Apps Settings page."
In a previous report from last year, this issue appears to have been fixed/worked on, but it's no longer working for me on Windows 10 x64 - 1803.
In the windows 10 integrated explorer, the function works just fine. No errors.
I've encountered this issue via pinning from the folder tree. I'm unaware of how to pin it from the file display mode. I assume via a right click context menu, in which I don't even have an option to do so.
Interesting. Seems some of my registry keys related to quick access got corrupted or deleted, which became apparent to me after you suggested using the Shift + Right click option, which wasn't working.
I ran a .reg key restore I found online for showing the quick access toolbar and it appears to be fixed.
No idea how that could have happened. Anyway, sorry for the false flag. Good to know it was just me.