DVD-R discs work and then fail in Panasonic DMR E85H

[herefordjw]

I continue to have a problem with my Panasonic DMR E85H and DVD-R discs. I typically record programs on the hard drive and dub to a DVD-R disc for future viewing. After dubbing a number of programs to a disc in EP mode, an occasional disc seems to fail. i.e., it doesn't always happen, but once it happens to a disc, I can't use that disc or access the programs on the disc. When I put one of these failed discs into the DVR, it takes longer than normal to read the disk. Once the flashing red and white light stops and I try to view the existing recorded programs with the Direct Navigator, the unit says UNFORMAT in the window and gives me the following message on the TV screen. "The disc is not formatted properly. Please format the disc in DISC SETTING to record." This obviously makes no sense since the disc was used a number of times previously and suddenly doesn't work. Also, a different, but same brand DVD-R works fine. FYI, I am using a Verbatim 8X DVD-R disc. Any help would be greatly appreciated.

[handyguy]

'This obviously makes no sense since the disc was used a number of times previously and suddenly doesn't work.'

You only get so many writes to a dvdrw. That is what you are using, right?

[herefordjw]

Sorry if I wasn't clear. I have put the disc in and recorded on EP mode a few times. Typically I get 8 programs on a disc and they are recorded individually. Once the disc is full (6 hours), I finalize the disc. On this particular disc I have recorded approximately 4 hours of programming in EP mode and should have two hours left. I can't get the DVR to recognize the disc. Consequently, I can't finalize what I have, I can't view what has already been recorded and I can't add to the disc to use the remaining space. I have probably recorded over 100 discs with this machine and this has happened 3 or 4 times with a DVD-R and once with a DVD-RAM disc.