Increasing the distance between the Hover Engines and the thing its stuck to will drastically decrease the force required to remove the Whitebox. Tools such as shims are useful for aiding separation. When trying to remove the Whitebox, sliding instead of pulling should also help dramatically. Once the Whitebox is removed, check the bottom for damage. If you see cracked or bulging Hover Engine bottoms, DO NOT operate your Whitebox until they are repaired.