On some systems, the Terminal workaround for Skype cannot make the necessary changes to Skype in order to allow virtual cameras to load.
If you followed Option #2 in the article about, and received error messages, you can use these steps to fix the problem.
Open Terminal (in Application/Utilities)
Copy and paste this command and press return.
sudo xcode-select --install
3. Follow the prompts to enter your computer's admin password. You won't see your password as you type it. Press return when done entering the password.
NOTE: If this command gives an error message about "command line tools are already installed", copy and paste this command and then press return:
sudo xcode-select --switch /Library/Developer/CommandLineTools
4. Copy and paste this command and press return.
sudo xcode-select --reset
5. Then, be sure to run the codesign command from the previous article again.