According to Chef Palak Patel of the Institute of Culinary Education (via Martha Stewart), anything that has “a very high water content, is not going to do well when frozen.” Potatoes contain a lot of water, and when they’re frozen, the water and starch separate, leading to watery results when reheated, explains the PennState Extension. That doesn’t mean you shouldn’t freeze any and all potatoes, as it really depends on the type and use of those potatoes.
For Patel, whether or not to freeze potatoes depends on how important they are to the dish — if “they are supporting ingredients in soups, stews, and sauces,” then freeze away, since they won’t affect the overall quality of the dish. But baked potatoes should never be frozen, as “ruptured ice crystals will lead to an unpleasant, watery consistency” and “they will become unable to hold a shape or form.”
If you must freeze baked potatoes, the Foods Guy recommends not freezing leftovers, and to dry the potatoes out first, not adding toppings, and wrapping each baked potato individually. DIYs also suggests consuming any frozen baked potatoes within a month of freezing for the best results.