Poor concrete surface preparation is the main cause of garage floor epoxy peeling. To form a mechanical attachment to the concrete, epoxy requires a clean and porous surface. If you don't have that, your coating is very certainly going to fail over time.
We don't mean a mop and bucket when we say clean; instead, we're talking about concrete grinding. Anything that is sitting on top of the garage floor, such as old coatings, oil stains, grime, and so on, will be removed by grinding the concrete.
While cleaning the garage floor, the concrete grinder is also opening up the concrete (making it porous), resulting in a clean and porous garage floor surface.
If your garage floor is peeling, the most likely cause is that the preparation for the epoxy garage floor was an acid wash. Acid washing concrete is a wonderful way to clean a garage floor and make it porous, but it isn't sufficient for epoxy preparation. It does not allow the epoxy to soak into and adhere to the concrete, so if you drive your car in on a hot day, the tires will lift the epoxy off the garage floor the next time you drive out.
When you concrete grind the garage floor, you open up the concrete entirely, allowing the epoxy to soak in and grip onto it, making peeling almost impossible.
The easiest technique to fix a flaking garage floor is to use a concrete grinder to remove the entire garage floor covering and return the concrete to its original state. As a result, you'll have a flawless substrate for your new garage epoxy floor.
If you paint over flaking epoxy, the new coating will attach to the flaking epoxy and continue to flake off; we mention this since it happens far more frequently than you might imagine. It's like painting a wall or door frame: if you don't sand it first, you'll be able to pick it off with your nails once the paint has dried.