I resolved the problem by right-clicking the Windows PowerShell & Command Prompt apps and clicking “Run as administrator”.
However, I now have a new problem; When I open the Linux distribution, it states the following:
“Installing, this may take a few minutes…
WslRegisterDistribution failed with error: 0x8007019e
The Windows Subsystem for Linux optional component is not enabled. Please enable it and try again.
See Install WSL on Windows 10 | Microsoft Docs for details.
Press any key to continue…”
Windows Subsystem for Linux is enabled in my notebook but I still get the message above.
The Linux distributions I installed & opened, and where I received this same message, are:
Debian;
Ubuntu 18.04 LTS; and
Ubuntu 20.04 LTS.