Any way to save an undercooked roast, cooked in crock pot and then refrigerated overnight?

Try to remember that time is never a true indication of doneness. You have to "temp" the food to be sure it is properly cooked. Recooking a roast should be fine. Stove top, oven, or back in crock pot for a few hours. Remember you are not roasting in a slow cooker. Like was said above, you are braising it. Beef, unlike some other meats, can be cooked longer. Putting hot food in the fridge to cool is not a great idea for anything. It warms the other foods in the fridge and can cause spoilage. To quick coo something Before putting in fridge, you can use an ice bath. The vegetables are more at risk for quickly forming bacteria than the meat. You should cool quickly and then wrap and put in fridge.

Sorry about that, old habit. It's shorthand for "Original Poster".

And I guess I used IMHO above too ("In My Humble Opinion").

Silly question, but what does "OP" mean? The question asker?

ChezHenry, respectfully, this is a discussion, not an argument, the purpose of which is for us all to learn.

Agreed one should *always* err on the side of caution when it comes to food safety. That does not mean USDA guidelines must be blindly followed verbatim if one understands the reasoning and science behind them.

Agreed it's not wise to put containers of hot food directly in the refrigerator but the OP already knows that and, considering the circumstances, what choice did she have? In doing so, she didn't endanger the roast, only the food already under refrigeration. The cooker insert cooled (slightly) more quickly than if she had "followed the rules". Next time I'd recommend transferring the contents to a not-scalding-hot container to reduce the thermal mass but that's about it.

Finally, the vegetables spent 5 hours in a cooker set on "high" and were undoubtedly well pasteurized. Mushy, but safe. To put it another way, except for the center of the hunk o' meat, we're just discussing common everyday leftovers. I've explained why the situation is perfectly safe. If you think my reasoning is wrong, please explain...

And finally, it's not just the Roast here! Its the vegetables, the cooking juices, the whole melange here, not just the outside of the Roast you are talking about. After the last go round on food safety, Food52 posted a great article. I propose they should post an entire section with knowledge, advice and techniques.

And I don't want to start an argument again here about food safety. Many, many people get sick from improper food handling. It is sound advice to err on the side of caution, and to promote healthy and knowledgeable info here, especially those of us who have training on the subject.
The cool down here is the major issue, it probably took 6-8 hours for this to get down to a temperature below the danger zone, an enormous amount of time for bacteria to take hold.

I too have a food handling certificate from NYC. The worst thing you actually did here was take hot food, in a hot liner and stuck it in your refrigerator. That is in addition to the fact that it was partially cooked - again it would be nice to know to what temp-but you were most likely still below 140 degrees, in the danger zone.
I concur that you should toss this, and not use it. Will you get sick? Who knows, maybe not. Can you get sick because of this handling? Definitely. And that's where everyone with professional knowledge on this board should side with-you shouldn't risk your health and those you're serving (I assume a roast is for more than 1 person and/or more than 1 meal).

A partially cooked roast (the cut, not the technique) does not present any danger. Here's why: Bacteria present on the raw meat are only on the outside surface, there's no way for them to get deep inside. Pasteurization of the exterior surfaces happens pretty quickly during cooking, no matter what method is used. It's the same reason why it's safe to serve a rare steak. Any bacteria picked up during cooling / refrigeration will be likewise dispatched during the second cooking cycle.

Pierino's specification of 130F is correct IMHO despite the fact the USDA says 145 minimum. No chef could hold a job if he cooked everything to USDA specs. To be clear, though, you need to understand the issues before bending the rules.

Poultry is an entirely different matter as is ground meat.

The USDA does not recommend partially cooked meats, poultry, be cooked again. Potential for bacterial issues is very real.

http://www.fsis.usda.gov/OA/news/2003/hotline_holiday.htm

This link above clearly mentions partial cooking.

I'm sorry you have to toss your roast. :(

OK. Thanks for your input, Sam and ChefOno. For some reason my question got posted twice. Will try and figure out how to delete one of them.

I concur. Or back in the slow cooker.

Just finish it on the stove. I think it'll be fine.