Hello, I am going to be as detailed as possible with my question. I have a Panasonic DMR ES10 DVD recorder. I have had many problems with DVD's that have been recorded on all of a sudden saying "unformatted". I use DVD-RW all the time, unless I am recording one movie or show and then closing out the disk. I have tried the Sony packs of 25 disks that come all together, and the Sony ones that come packed in a box of 10, with individual jewel cases. I have also tried Memorex. Many of these are almost full DVD's, and then all of a sudden when I place them back into the recorder to add to them,