In my last post on this subject I had said that I had tried to contact the company that manufactured the disks. Since that time, I have not received a response. Here is my note to them:
I've been a TDK user my whole life. I have never experienced any issue with your cassettes, DAT, CD-Rs in many personal and professional applications.
A few months ago I bought one or two spindles of 1-16x 4.7GB disks.
Over a period of time I burned, verified and tested about about 150 disks of both data, audio and video successfully I placed them back on a spindle.
When I went to retrieve a disk I discovered it wouldn't read. I became concerned and started testing all the disks. about 100 or so disks were no longer readable. They were tested on 5 computers with different OS' and the video disks were tested on two DVD players.
I have researched this topic for two weeks now and have not found any information on disks being created, tested as working, stored and tested as not working within a three month period.
As a professional who has used optical media for some time, I am at a loss as to 1. what could have possibly happened 2. what to do to possibly retrieve the data.
I would greatly appreciate it if you could forward this around the company and see if you can help find a solution.
All disks were burned on two Macintosh's running up to date versions of Roxio Toast. The numbers on the disks read CMDR47G-CTMW01-104 3115
Thank you for your attention.
Alan suggested I post in the forums at doom9.net which I have done. Although I have not found a solution, I have at least read a fair amount of interesting information and the people on the forum have been supportive.
I found a Japanese application called DVD Media Inspector which allowed me to locate who actually manufactured the batch of disks. I was able to do decoding by comparing the data with information on this site.
Meanwhile the handful of disks that aren't totally dead are dying fast. They take minutes to read and many give errors if I try to copy them and I am still searching the house for all disk from that batch. I am at a standstill as to whether I will be able to trust DVD back up again.