Oxford Instruments released the ImarisViewer. It is a subset of the Imaris functionality, essentially constraint to the 3D visualisation capabilities. But it a free version, that allows you browse your datasets you processed with Imaris.
Windows users being part of SECMED or BIOL can install the ImarisViewer via the Baramundi Kiosk.
Mac users can find the installer on our download page (visible only from within the UNIFR domain)