I have a paid-up installation of Matlab R2015a and many toolboxes. I want to try two other toolboxes and requested/received a trial for them via the License Center. When Idownloaded the trial , I seemed to have to download Matlab too: popup window said 'Removing files for Matlab', followed by a popup window saying 'Downloading Matlab', ... etc. The trial installation seemed to undo my 'legitimate' installation, yet the trial toolboxes were not available after the installation. What is the correct way to install only trial toolboxes while leaving my existing installation intact?