Using KDE on Arch. USB drives are read without issue but, when trying to open a disk (CD or DVD) using a built-in laptop disk reader, the disk won't open in either Dolphin or Thunar.

The Device Notifier correctly shows that a disk has been inserted and shows two options: to open in VLC or to open with File Manager. Select the File Manager option (which points to Dolphin), and 'kioclient' examines for a few seconds and Finishes with no errors. Next, 'kioexec' automatically starts to examine it: for roughly three seconds. An error popup then displays: which says "Error - KIOExec? File or folder / does not exist".

If I start Dolphin and enter "/dev/sr0" into the address bar, I get "What do you want to open the file with" in a pop-up. In Thunar, I get a pop-up which asks "Open sr0 and other files of type 'block device' with...".

I've checked Google and have found no existing articles / posts which seem to involve CD drives, specifically.

I actually just found my solution. Still posted, since I found nothing on this...so that others can find the solution more easily.

In Arch w/ KDE, installing Dolphin DOES NOT also install cd/dvd handling. KDE does not use GVFS, natively: it uses KIO, instead. To allow KIO to read Audio CD's, etc, install the "audiocd-kio" package: as in "pacman -S audiocd-kio".

See https://wiki.archlinux.org/index.php/Dolphin for more details.