"The solution is already installed on this system as a managed solution" error in Dynamics 365

When attempting to import a solution in Dynamics 365, you encounter the following error:

"The solution is already installed on this system as a managed solution and the package supplied is attempting to install it in unmanaged mode. Import can only update solutions when the modes match. Uninstall the current solution and try again.

Error code 80048041"

As mentioned within the error message, the solution is already installed on this system as a managed solution and the package supplied is attempting to install it in unmanaged mode. Import can only update solutions when the modes match. 

Example: You create a solution in your development environment and export it as managed. You then import the solution to your production environment. If you later export this solution from your development environment as unmanaged and try to import it into your production environment where the solution is already installed as managed, you will encounter this error.

Once a solution is installed in an environment as managed, you should only import the managed version of the solution into the environment. 

Import a copy of the solution that is the same mode. In the example provided in the Cause section, import would succeed if the solution being imported was a managed solution.

For more information about managed and unmanaged solutions, see Unmanaged and managed solutions.