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Lz0

macrumors regular
Original poster
Jul 20, 2002
177
4
Melbourne
In years past I've made DVD backups of files thinking that if I kept a computer with an optical drive that I would be able to access those files at any time in the future. Not sure of the MacOS at the time.

Just an FYI, my oldest backup CD is dated 1995.

Today I'm in need of some files that I know I backed up to DVD using the MacOS finder in 2005. To make it clear I didn't use Toast I used the MacOS to burn the DVD's. I have the DVD's in hand but my 2011 iMac only recognises the DVD's as blank and want's to initialise them. This iMac has a working optical drive.

Why is this so, and does anyone know how to fix this problem? And what's the point of making backups if in only a few years time you can't access them?

Is there a way I can access my old backup DVD's?

Cheers Adrian
 
First, what software on your 2011 iMac is telling you that it recognizes the DVD as blank?

Can you "see" the DVD with Disk Utility? If so, this link shows how to copy files from the DVD to a file on your desktop:

 
In years past I've made DVD backups of files thinking that if I kept a computer with an optical drive that I would be able to access those files at any time in the future. Not sure of the MacOS at the time.

Just an FYI, my oldest backup CD is dated 1995.

Today I'm in need of some files that I know I backed up to DVD using the MacOS finder in 2005. To make it clear I didn't use Toast I used the MacOS to burn the DVD's. I have the DVD's in hand but my 2011 iMac only recognises the DVD's as blank and want's to initialise them. This iMac has a working optical drive.

Why is this so, and does anyone know how to fix this problem? And what's the point of making backups if in only a few years time you can't access them?

Is there a way I can access my old backup DVD's?

Cheers Adrian

not sure but I think the disk burning / reading capability you need was on Sierra.
I would try to find a Mac repair shop in yr area and see if they have a Sierra installed device you can borrow / rent.
 
After 15 years, the dyes on the CD may have faded to the point that the DVD/CD drive can't read them anymore.

But... as mentioned above... try ANOTHER DRIVE.
Perhaps on another Mac.

Questions:
What Mac/drive are you currently using?
What version of the OS are you currently using?
Do OTHER CDs or DVDs mount (and can be read) without problems?
 
Old, writable CDs can (and likely will) lose their data in a lot less time than 23-24 years! They're not made in the same way as commercial, read-only music and video CDs/DVDs or CD-ROM or DVD-ROMs.

I started noticing the degradation on late-90s burns in 7 or 8 years.

 
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not sure but I think the disk burning / reading capability you need was on Sierra.
I would try to find a Mac repair shop in yr area and see if they have a Sierra installed device you can borrow / rent.

Niji you must be able to read, all the other replies are people replying to the voices in their heads.

MacOS Tiger 10.4 was probably the OS at the time. The DVD drive is working and I can mount and read from many other CD's and DVD's. The DVD's in question have not degraded in time, they are of different brands and formats e.g. DVD-RW and DVD-R. I was under the impression DVD and CD media had a half life of about 200 years.

But the question has to be, why can't High Sierra read DVD's burnt in Tiger?

I will endeavour to find a solution and post the results here.
 
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Today I'm in need of some files that I know I backed up to DVD using the MacOS finder in 2005. To make it clear I didn't use Toast I used the MacOS to burn the DVD's. I have the DVD's in hand but my 2011 iMac only recognises the DVD's as blank and want's to initialise them. This iMac has a working optical drive.


DVD-Rs degrade and may not be readable after several years. Its quite possible your optical media has died.

Keeping stuff on old media (be it tape, optical media or hard disks) and not refreshing it to new media after say 5 years is a mistake.
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I was under the impression DVD and CD media had a half life of about 200 years.

That is not correct. Some say as few as 30 years (not half life, max life), but that also depends on proper storage, no physical damage, etc.

e.g.

An accelerated aging study at NIST estimated the life expectancy of one type of DVD-R for authoring disc to be 30 years if stored at 25°C (77°F) and 50% relative humidity.

ref: https://www.clir.org/pubs/reports/pub121/sec4/

Guessing you aren't storing your DVD-Rs in a temperature and humidity controlled environment? Also that is for DVD-R, not RW media. RW media (if you used that) has a much lower life expectancy.

Either way, if your only copy of something is on a single optical disk, then this is a mistake. Maintain multiple copies, and refresh important stuff to new media/other locations every few years if you really need it.


As suggested: try another drive. Just because your drive works on other media, doesn't mean it works on ALL media, and if your media is partially degraded (which is likely, given you're talking about 15-25 year old data here, and attempting to read with a 9 year old drive), another drive may have better results.
 
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Niji you must be able to read, all the other replies are people replying to the voices in their heads.

MacOS Tiger 10.4 was probably the OS at the time. The DVD drive is working and I can mount and read from many other CD's and DVD's. The DVD's in question have not degraded in time, they are of different brands and formats e.g. DVD-RW and DVD-R. I was under the impression DVD and CD media had a half life of about 200 years.

But the question has to be, why can't High Sierra read DVD's burnt in Tiger?

I will endeavour to find a solution and post the results here.

i will continue to think about what might be causing this.

in the meantime, there is on amazon (japan, sorry...) a drive specifically built to operate using High Sierra system made data. (in the comments section several of the users with similar use case scenarios such as yrs have also confirmed it works even as late as Mojave.
maybe there is this same model sold in other amazon stores.
i was amazed to see a DVD player referencing High Sierra on sale on amazon in this year 2020 so your assumption that apple changed its writing format somehow around that time is given credence, thus the need for this even now.

in japanese (but with some english):
 
I've been using Sony CD-R and DVD-R since 2000 and no problems. I keep the backups away from sunlight. Make sure the drive you are using is compatible. If you used iPhoto backup feature you might have to use a Mac and view the images in Image Capture. Other files...I hope you just saved by drag and drop method cause it will be easy to retrieve.


I wonder how long too because Apple is famous for destroying the flow :(
 
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