Zend certified PHP/Magento developer

‘Required parameter ‘theme_dir’ was not passed’ when creating new theme

I’m running Virtualbox Ubuntu 18.04.03 with Apache on Windows 10. I have an installation of Magento 2.3 running.

My goal is to adjust an existing theme that is created for my company since we’re having some changes in our brand design.

I started creating a shared folder between the VM and my pc. The path where my theme is located on the VM looks as follows: app/design/frontend/COMPANYNAME/default. My registration.php etc are inside the default folder.

However, after selecting my ‘newly’ created theme in the backend I get the following error: Required parameter 'theme_dir' was not passed. The theme files are probably not the issue since they are working on our live system.

I’m aware that there are a lot of topics about this error already but they’re all about on how to unselect this theme instead of fixing the error for the specific theme selected (I know about the DB operations etc).

I’ve been trying for hours to figure out why I can not set this theme so I hope I can find any help here.