Plastic SCM is already installed but when you try to use the Unity plugin for Plastic SCM, you receive a “Plastic SCM is not installed” error.
There are several causes we have seen in the past for this error to occur.
Things to check:
1. Perform a reboot of your machine
2. Check that you have the Plastic client installed and it's able to connect to your repository server and list your repositories.
3. If you are connecting via SSL port, make sure that the certificate is already installed in your client machine before using the plugin.
If you are still having issues, please report this as a support ticket and we will be happy to help.