As already pointed out, you can't reverse entropy so you certainly won't find a scientific explanation.
Scan objects and remember their states, then recreate exact replicas from this data
Your machine, however, could work by continually scanning the area within a 2ft radius of itself and remembering the position and state of each object within this area. This would require a lot of precise scanners to determine all this information. Think of it like an auto back-up of your pc. Then you knock your mug over and, instead of cleaning it up. You activate your machine and get out of that 2ft area before it sucks up the offending material (the object in a different state) and creates an exact replica of what the object was like at the time you want it restored to.
It would be easier if particular objects could be put into a machine to be scanned. You buy a new laptop and instead of insuring it you just plonk it in your Entropy Reverser™ which scans it for you. Then if it breaks you just have to get it to make you a new one (by providing the bits of the old one perhaps).
This is, by no means, actually reversing entropy. You would need to put a lot of energy in to do this and provide the raw materials (by giving it the object which broke or buying additional materials).
This isn't a scientific explanation but not beyond belief. We already have 3D printers which, given a 3D scan, can print out most objects and we have the scanning technology. Still need a bit of a jump to recreate absolutely anything though, plastic is easy to manipulate but 3D printing a mug requires ceramics and once the clay has been fired it cannot be returned to clay so fresh clay is needed.
It depends how far in the future and how much hand-waving you want your world to be.