I have a fair amount of experience with the freezer solution -- I used to fix computers for a living long ago -- and for the limited use and purpose it serves, it can work really well.

If you have a drive that has intermittent read failures, meaning it will start to read a file and then give a read error, in some cases freezing the drive for several hours will enable you to read the bad sectors long enough to copy them off to another drive. Also, if you have one of the famous Western Digital drives that makes the awful drive-head-seek-click-of-death sound, it will sometimes allow you to access data on a drive with that problem. And I've heard of it temporarily reviving a drive where the spindle motor is dying and it won't spin up. But it will only help you if those are the specific circumstances.

The issue seems to be that freezing the drive makes the sectors easier to read for some reason (physics was never my thing.) But the problem is, the drive will heat up within about two or three minutes of being powered up and you'll get the read errors again, so you either have to copy your files really fast (if there are only a couple of smaller ones) or resort to a more drastic procedure. You can put the drive inside several layers of plastic bags, each individually sealed with a twist tie, and then put the entire assembly, bags and all, (with data and power cables attached) into a bucket of ice, submerged except for the top inch or so of the drive where the cables are coming up.

I've had several of the "click of death" drives that I revived long enough to get crucial data off that way. But if the problem is a different one -- the 'drive not formatted" error, or corruption in the file allocation table, then the freezing solution won't help.

Hope that clarifies things.