Grohe makes several kinds of shower valve handles. While some are basic in design, others are more complex. However, all disassemble using a set screw that attaches the handle to the faucet's cartridge. Finding the set screw is perhaps the most difficult part of this process. If you need to repair the faucet or replace the cartridge, taking the handle off is the first step, and it's a basic one to master.
Things You'll Need
Allen wrench, 2mm (size may vary by model)
Turn off the water that flows into your shower by closing the incoming water line in the home.
Find the handle lever's set screw. This is the small, round screw on the side of the lever. It is usually underneath the handle lever or on the side of levers with a round base. Once you find the screw, insert an Allen wrench into the screw head and turn counterclockwise until the screw is no longer threaded in the mounting hole.
Take out the screw once it is completely unscrewed and set it in a place where you won't lose it. You'll need the screw to reattach the handle if you plan on rebuilding the faucet once the handle is off.
Pull on the handle to slide it backwards and off of the faucet stem. Once the handle is off the stem of the faucet, look for the adapter under the handle. This is a small part with a rod, and only certain handles require one.
Unscrew the mount screws for the adapter with a screwdriver and pull the adapter off the faucet stem.