Do you love home-made mashed potatoes when they’re first made but hate how the soft, creamy texture that drove you to make them from scratch in the first place, is replaced by a dry, lumpy, unappealing texture when you reheat them?  I’ve solved this problem…

The cause of it is not the storage or refrigeration; it is inadequate *preparation* for storage and refrigeration.

What you need to do is this:
While you’re serving the mashed potatoes, try to keep them as warm as you can.  It’s okay if they’re not hot, they just should not be left to get cold yet.  Then when you’re done eating, make some more hot milk and butter mixture like you would use to make more mashed potatoes (or, just reheat it if you had excess left over from when you made them originally).  Now, using your mixer that’s still out, re-make your leftover mashed potatoes, adding the hot milk and butter mixture to again achieve the creamy texture that they originally had when you first served them.  Mix in just a bit more milk and butter (1T to 3T depending on how much leftovers you have) to make them just a slight bit softer than you want them to be for eating.  NOW store them in the refrigerator.

When you reheat them in the microwave and mix thoroughly, they will have that creamy, almost identical texture as if you had just now made them.  I kid you not.