Install 30-day toolbox trial when a MATLAB license exists

I have a standard MATLAB license (R2015b) and received a download link from MathWorks for two toolbox trials I requested. The default folder in the installation pane for the toolbox install is the one into which my standard license was installed. When I click "Next", I get the error "Cannot install in the specified folder because there may be files remaining from a previous installation." Is there a different folder into which I should be installing the toolboxes?

[Walter Roberson]

When you requested the trial, did you specifically request it against R2015b? Mathworks does not like to give trials for version more than a year old, as they seldom agree to sell versions that old.

More typical would be that you would get a trial of the current version of MATLAB along with the toolboxes you are interested in, and you would be expected to buy against the current version (or no more than a year old); to buy toolboxes now you would be expected to pay retroactive maintenance to present.

[J.S.]

Yes, I was sent R2015b trials of the toolboxes to test with my existing MATLAB R2015b license.

[Image Analyst]

Call them. They will talk/walk you through every step of the installation if you ask them.