Non-Qubes-Whonix Known bugs
Mounting (CD / DVD) Devices
If the device auto mounter is broken, see if
Start menu ->
System Settings ->
Removable Media helps.
The following workaround can be used.
sudo mkdir /mnt/cdrom
sudo mount -o ro /dev/cdrom /mnt/cdrom/
Using the ro flag will mount the CD / DVD in read-only mode. If a CD / DVD is not being mounted, then drop the "-o ro" parameter.
Help fixing this bug is welcome! (ticket)
Network Manager Systray Unmanaged Devices
Short answer: Unmanaged devices are unrelated to Whonix functioning and should not concern the user.
Long answer: 
Suspend / Hibernate Issues
Short: Avoid suspending or hilbernating the computer or Whonix VMs while Whonix is running.
VLC / Video Player Crash
The following workaround can be used; this is the default in recent builds (like Whonix 14). 
Whonix does not use network manager to manage either eth0 or eth1.
- In Non-Qubes-Whonix, networking is managed by ifupdown.
- Qubes-Whonix uses a custom /lib/systemd/system/qubes-whonix-network.service and is unaffected by this issue.
To reduce confusion, the ideal Whonix default would either: prevent the systray item starting, hide the systray item, or suppress the information being presented. Network manager is installed so users can easily setup VPNs with its intuitive graphical user interface.
All attempts to fix this long-standing issue have failed. Help is welcome to fix it.
Fix Unmanaged Devices Network Manager