1.) ISO pop-up box does not appear in step 4.15
    Solution: Go to the storage tab in the virtual machine settings and attach the ISO file

2.) Guest additions CD can not be mounted
    Solution: CD is already mounted, open the CD and press run software in the file explorer

3.) Kernel Error -1908
    Solution: https://www.howtogeek.com/658047/how-to-fix-virtualboxs-%E2%80%9Ckernel-driver-not-installed-rc-1908-error/

4.) Kernel CPU error - Wrong CPU detected (x86)
   Solution: Select Ubuntu 64-bit, not 32-bit

5.) No menu present in Virtual Box when in the virtual machine
   Solution: The machine started in scaled mode instead of windowed mode. Can press Cntrl-C to switch to windowed mode, which displays the menu.

6.) Synaptic package manager - Quick filter box does not display after (sudo apt-get install apt-xapian-index and sudo update-apt-xapian-index -vf) commands.
   Solution: seems this is just a time issue. For whatever reason, the quick filter box may not appear until after some restarts. 

7.) Hash mismatch in sudo apt update/(I/O error during install)
   Solution: There seems to be a bug with VirtualBox when Hyper-V/Windows linux sub-system is activated. The stack overflow discussion is here  https://askubuntu.com/questions/1239382/error-when-installing-ubuntu-20-04-in-virtualbox#:~:text=The%20installer%20encountered%20an%20error,or%20a%20faulty%20hard%20disk.

8.) Minimal install vs. full install: Ubuntu provides the list of removed packages at https://people.canonical.com/~ubuntu-archive/seeds/ubuntu.focal/desktop.minimal-remove.