Why do I get the error "The feature 'RTWTesting' has already been registered." when launching Simulink?

When I tried to launch Simulink and opened Simulink model, I got the following error and couldn't open it.

Error using open (line 146)

The feature 'RTWTesting' has already been registered.

Answer 1

[MathWorks Support Team]

At first, please try initialization for MATLAB preference folder and MATLAB path.

To initialize MATLAB preference folder, please rename it. You can confirm MATLAB preference folder.

>>prefdir

To initialize MATLAB path, please run the following commands from Command Window.

restoredefaultpath
rehash toolboxcache
savepath

If the issue hasn't resolved, you might fail to install MATLAB/Simulink.

Therefore, please try clean installation MATLAB as an administrator referring the following URL.

https://jp.mathworks.com/matlabcentral/answers/131519-how-do-i-perform-a-clean-installation-of-matlab