I cut up vegetables and put them along with a chuck roast in a freezer bag, to have a meal ready for the crock pot when I had surgery. I took the bag out of the freezer last night, dumped the ingredients in the crock pot and refrigerated until this morning. It has been cooking on low for 5 hours and all of the potatoes are black. After researching, I found I should have blanched them first.  Are they still good to eat?

The Farm Babe - How to Know if Your Potatoes Have Gone Bad

Because you just put them into the freezer, the cell structure hasn’t broken down so while the visual looks bad, they are probably still safe to eat. Same thing happens to onions when frozen from raw. Will they still taste good? Not really. I hate to be the bearer of bad news. If I had any extra potatoes I would cut and sauté them and then add the pot roast to the pan to warm up together and toss the old potatoes. I often add some canned beef stock to flavor the potatoes at the last minute too.