I have a very strange problem reading data from my backup CD-ROMs. When I explore the CD, only a fraction of the files on the CD show up. So for example, I put in a 700 MB CD with regular files (such as MP3's and pictures), and Explorer only displays about 85 MB worth of data. Data is clearly missing from the Explorer display. I tried using the Command Line Console and the same problem occurs. I cannot access all of the data. When I click on properties, it indicates that about 700 MB of the CD is used which does show that there is more data on the CD.

Some Notes:

- This is the first time in my life that I've ever witnessed this problem.
- The last time I tried to access data from these CDs was a few months ago and I was able to. Never had problems ever.
- The majority of these CDs were burned about 2 to 4 years ago.
- Properties shows that the CD is full.
- Properties shows a file system of "USIUDF". I don't know what this means.
- The main difference with my PC between the last time and now is that I re-installed Windows XP because I lost my old HD.
- This problem occurs when I use both my new DVD-RW and my old CD-RW that I had before that I used to burn these CDs.
- This does not happen on all of my CDs, only some of them.
- I have yet to try to access the data using another PC.

This is very frustrating and I'm afraid some valuable data may be lost forever. Please help me, thanks!!!

I believe the first thing you should do is attempt to read those problematic CDs using other systems.

If the same problem occurs on 3 or 4 machines, I'd conclude that your CDs are "bad".

Just FYI, the layer on which information is recorded is susceptible to decay due to light and temperature (and other factors but those are the two "biggies" ). It is therefore possible that the layer has decayed, in that case, your data is very likely lost. You need to ascertain if this has happened, testing the CDs in multiple machines will tell.

HTH.

i will try them at work tomorrow. one thing i noticed, when i click on properties, it displays as file system "USIUDF". I have no clue what this mean.

Just run it under hot water or use an optical cleaning solution to clean the surface.

Sounds like the usiudf file system is an obvious symptom... i would suspect some software change is the culprit...

How were the cd's originally burnt? Just a standard burn or using packetwriting software (InCD or similar), or using the winxp burning wizard (shivers....)

There is a chance that when you reinstalled windows that the software required to read them correctly (if they were packetwritten) is not the same or newer...

Did you get a different package with your DVD burner and install that?
USIUDF is apparrently some sort of uLead disk format, but i have no experience with it.

i believe they were burnt using DirectCD drag and drop. I think it was Roxio EasyCD creator package.

after re-installing, i use Ulead. But if there was a file system issue, how come i can still access some of the data? and on other CDs, i can access all of it.

well dude if the problem is coming from the cd burning software u used i urge that u grab some bucks from ur wallet and get a copy of Nero

Perhaps it's a driver.

GOOGLE!

i tried to access the data on another 2 PCs at work. on the newer PC, i cannot access any files at all. On an older PC, i was able to access all of files so far.

would this really point to a driver related issue then? do i still need to be concerned about decaying on the CDs?

i've seen problems like this in multi-session cds. The recording format could be an issue too. You should always record in iso9660.
The program you used before cound have installed some shell extension (driver) to allow drag and drop recording directly from windows, for instance. That explains why you were able to read and now you're not

Just read the data from the machine that works, burn new disks then toss these in the trash. Or, use the original softare to read the data. Don't beat your head against sharp corners for no reason.

The fact that you can access all of the files in an older PC makes it sound as if the problem is driver related.

Here is something that may help,

http://www.ulead.com/tech/general/data_add.htm

This page points to a ULead packet writing driver that may very well be what was used to create the CDs you cannot read. By installing the driver on your machine you may be able to read the data again.

Since you can read the CDs just fine in an older PC, I don't think material decay has anything to do with the problems you've experienced.

HTH