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Create multi-session CD-Rs in the Finder Desktop
To make multi-session CD-Rs in OS X, you do not need the CLI or the hdutil (as explained in previous hints 1 and 2).

First burn a CD as usual in the "Finder" with whatever data you want on it. Then when you want to add data, just create a blank DMG (using Disk Copy) of whatever size you need to hold that data. Of course, the size you specify must fit on the partially burned CD. Put the files you wish to burn on the DMG. Unmount the DMG and then use "Disk Copy" to "Burn Image". Put in the CD to which you wish to add the data.

"Disk Copy" now says "Click the "Append" button to burn", and the button says "Append" instead of "Burn". And there you go, a multi-volume multi-session CD-R or -RW burned in OSX with no additional software required!
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Create multi-session CD-Rs in the Finder | 41 comments | Create New Account
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Top Hint
Authored by: dave@mmu on Jul 18, '02 08:25:01AM

Excellent.. you get 5 merits stars!

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it just works... doh!
Authored by: JayBee on Jul 18, '02 08:34:11AM

/me tears hair out and screams:

Why didn't I think to try this? WHY??? FOR THE LOVE OF GOD, WHY???!?!?!?!????


/me trashes perl script he had to do the job before today

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Authored by: Olianthe on Jul 18, '02 11:06:38AM

Why is it not documented by Apple. Is there a lot of other tricks like this one hidden somewhere?

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I'd love this, but...
Authored by: simX on Jul 18, '02 11:46:18AM

... it doesn't seem to work for me. I just inserted a CD-RW which I had already burned to, and I made a test disk image to see if it would show the "Append" button.

Unfortunately, when I put the CD in, all it says is "This disc is not writeable" and then ejects it. And yes, I put it into my CD burner. :p

Is there some special format the .dmg has to be in, or what?

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I'd love this, but...
Authored by: eddydasquige on Jul 18, '02 11:50:47AM

I haven't played with this yet, but I would assume that you have to start with a blank CD-RW, or that the previous sessions should have been burn in the same way. So if you existing partially burned CD was done, say, in Toast, then it will only work in Toast and not with this finder method.

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I'd love this, but...
Authored by: simX on Jul 18, '02 01:23:35PM

But I DID! This CD-RW was burned VIA THE FINDER!

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I'd love this, but...
Authored by: swilcox on Jul 18, '02 01:55:53PM

I burned a CD using the new .Mac backup software. Then I tried this hint. It worked.

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I'd love this, but...
Authored by: MtnBiker on Jul 18, '02 07:50:52PM

by new software, what do you mean? Is this a 10.2 feature?

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Ok... what am I doing wrong?
Authored by: snit on Jul 18, '02 11:46:51AM

I tried this and can not get it to work... never seems to say append. Just tells me the disk is not writable. Any ideas?

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Missing ingredient???
Authored by: haumann on Jul 18, '02 12:06:48PM

I'm getting the same "this disk is not writable" message and no "Append" button. Apparently this hint does not tell the whole story. Will Paul Harvey please step forward and give us the rest of it?

John at Wood-n-Shavings, Inc.

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Doesn't seem to work
Authored by: dr_turgeon on Jul 18, '02 12:37:27PM
disc not writable
Could it be we need to have something installed via cli first?

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Doesn't seem to work
Authored by: swilcox on Jul 18, '02 01:54:06PM

I haven't installed anything via the cli, and the hint worked for me like a charm. PowerBook G4/667, OS X 10.1.5, built-in CD-R.

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Authored by: wayneyoung on Jul 18, '02 04:42:26PM

Perhaps one must have the Apple built in drives?

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Authored by: CaptCosmic on Jul 18, '02 06:00:06PM

I haven't had a chance to try this tip out on my CD Burner at home, but I would guess that it has to do with the disc having been closed when it was burned. If you close the disc when you burn it, nothing else can be written to it. However, if you don't close the disc, then additional sessions can still be written to it.

If I get a chance, I'll verify this when I get home. Or, you can check it for yourself and let everyone know.

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Hidden options
Authored by: Uncle-D on Jul 18, '02 10:50:08PM

There's an hidden option in Disk Copy
(which seem to be present in Jaguar, base on some screen shot)

Add to the Disk Copy preferences:

The following two lines:
<key>Burning Force Disc Close After Burn</key>

There's two other hidden options which I haven't tried:
(which also seem to be present in Jaguar)
<key>Burning Skip Final Free Partition</key>
<key>Burning Optimize Volumes Before Burn</key>

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Hidden options - YES! Now it works!
Authored by: JB Cheong on Jul 19, '02 12:04:44AM

Like some of you, I couldn't get the trick to work too.

So I tried the hidden option as mentioned by Uncle-D. I use PrefEdit to add it into the preference file.

The "Append" button magically appeared when I burn the second session, and the third and the forth...!

After burning the third session, I inserted the disc into my Rev. B iMac which has a CD-ROM. All three sessions mounted nicely. Therefore it appears there's no need to "close" the disc at all.

I further confirm the hidden option does work as advertised by setting the option to true, ie, force close the CD after burning. Bang, I can't append a fifth session after that. That being the case, it therefore explains why previously burned (and force closed by default) disc will not be allowed to append new sessions.

My tests were all performed using a CD-RW disc, an IDE SONY burner, and the first session was burn in DiskCopy instead of Finder.

So, a big THANK YOU to uncle-d for your tip!

I wonder what the other two options do...

JB Cheong

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Hidden options - YES! Now it works!
Authored by: bluehz on Jul 19, '02 01:49:31AM

No luck here either - tried it first with no mods - no luck. Then tried the .plist mods - still no luck. Tried it on both internal CD-RW and external FW CD-RW. Sure would be nice if we could get some workable details here.

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Hidden options
Authored by: Steve_Jam on Jul 19, '02 03:26:39AM

The newbie asks: after opening com.Apple.DiskCopy.plist with TextEdit, where in the text do you actually add those extra few lines? At the very end?

Thanks for help,


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Hidden options
Authored by: Ken Knoblauch on Jul 19, '02 07:19:11AM

With great naivity, I went ahead and added the two lines that you suggest in the Disk Copy preferences file, using vi. When I looked at what had been saved, it looks like the files has been altered, not just appended to. An option that was there before now seems absent. With additional naivity (you can call it stupidity now), I had not made a temp copy of the preferences file. Can someone suggest how to recover a copy of the previous one? I know that it is lost on my system, but perhaps there is a default .plist for Disk Copy that is available or that someone would be willing to send or post. When I tested it with 'file', it indicated that the file was in ASCII. Thanks, if you can help.

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Hidden options
Authored by: gvitale on Jul 19, '02 08:21:39AM

Trash it; it will be recreated the next tine you open DiskCopy, with default prefs

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More info needed...
Authored by: jiclark on Jul 18, '02 11:56:43PM

I have not tried this, but it seems there's some details missing. When I burn a disc in the Finder, I don't get any "close" option. It just says "Burn", I click it, it burns it, and mounts it on the desktop when it's done. How do we get it to not "close" the burn when we use the Finder the first time? Could the author (and/or editor) please chime in with a clarification?

Many TIA,

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More info needed...
Authored by: gjgallego on Jul 19, '02 08:26:11AM

I tried this and it didn't work on a CD-RW, but when I tried with an old (really old), cheap CD-R it worked beautifully. Go figure!

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It works only if ...
Authored by: gvitale on Jul 19, '02 08:45:08AM

... I burn the first session with Disk Copy from an .dmg (or .img). Apparently DiskCopy default is leave the disk open when burned from an immage (at least in my system there is no need to add the:

<key>Burning Force Disc Close After Burn</key>

option to DiskCopy plist).
I must say that I do not get how this works when you burn the first session from the Finder: at least in my system, this results a closed disk, and there is no way to add anything to a closed disk. I looked hard for a plist of this Finder "behaviour", but I could find none; it must be somewere if this works for some and not for others.
Anybody any idea?

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It works only if ...
Authored by: bluehz on Jul 19, '02 11:00:22AM

I can verify that this process DOES work IF YOU DO IT COMPLETELY IN DISK COPY!

1. Create blank dmg with Disk Copy - copy files to image. Unmount image, burn cd from Disk Copy.
2. To append another session - create a new dmg (or you can even use the old one - if names are not changed though you will get volume names like Test, Test 1, etc as mountpoints), copy files to image, unmount image, burn cd from Disk Copy - disk copy will spit out CD drawers - insert previous CD and close tray.

Interesting note - first off - you immediately see a difference in teh first session when you will notice that Disk Copy uses terminology in its dialogs like "Burning Session, closing session, etc". After the first session is burned and mobing on to the others I noticed the disk is automatically noticed as a multi-session. I am never preseneted with the dialog to "append" ...instead it immediately starts burning the disk.Also - the multi-session CD mounts fine in OS X 10.1.5 even without closing the disk.

FYI - I am using a QUE 24x/10x/32x CD-RW in an external ADS Pyro FW case running off a G4/400.

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It works only if ...
Authored by: bluehz on Jul 19, '02 12:04:15PM

I am doing a little experimentation - where does the Finder store the temp disk img it creates when you insert a blank CD and let the Finder "prepare" it? I remember in OS 9 you could easily find the tmp disk img in the System Folder, but I can not find it in OS X. I am wondering since the Finder always prepares disk for full-volume (e.g. 650mb) if maybe that is why the Finder disk burns are failing - I mean maybe the Finder senses the disk being full (even though youmay only be burning 10mb) and auto-closes the disk instead of leaving it open for further sessions.

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It works only if ...
Authored by: gvitale on Jul 19, '02 12:30:24PM

look for somenthing like .Temp_1234.dmg in your currently working directory

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It works only if ...
Authored by: bluehz on Jul 19, '02 07:02:09PM

serached everywhere - still not finding that Disc Burner tmp img....any ideas....anyone?

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It works only if ...
Authored by: mahakali on Sep 23, '02 06:51:41PM
Did you try to look inside /private/tmp folder? It's an invisible folder, but you can opt to make it visible by either using TinkerTool or type this command on the terminal:

defaults write AppleShowAllFiles 1

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Snipe hint?
Authored by: dr_turgeon on Jul 19, '02 10:29:16PM
With so many replies and conflicting instructions, I wonder why or how an Editor's Note hasn't shown up for this "hint". Nearly every other hunt has one!

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Authored by: VEGx on Jul 20, '02 05:47:43AM

This is ALL you have to do:

1. Make a .dmg
2. Put files in
3. Burn it on a blank CD (-RW) from !!!!
4. Make another .dmg
5. Put some other files in
6. Burn this .dmg again from
7. Repeat 4.-6. as many times you can until the disc is full

That's it.

[My problem now is, that it worked all fine, all my Mac CD-ROMs read it... But I can't read the CD at school [where they have becursed PCs]. Has anyone tried this??? Any hints? Thanx]

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The authors low-down
Authored by: joesim on Jul 20, '02 02:22:05PM

OK, I am the author of this tip.

And NO there were no special features, tricks, or PLIST hacking done to get this to work. This has nothing to do with 10.2.

You do not need to burn the original burn from DC, you can do it straight from the "Finder".

I think one of the previous post had it correct. It probably has to be a built in CDRW drive. Externals probably have a different process within Mac OS X.

I have tried this on 2 PMG4 QSs with CDRWs, 2 different FP iMacs and an eMac. The OSs ranged from 10.1.3 Server to 10.1.5 Client. All work just the way I discribed earlier. You will notice when burning a CD in the "Finder" at the end it says "Closing Session" not "Closing Disk".

I will try it on my CUBE and Ti at home with my external CDRW (Yamaha 2100E). It could be that this "Feature" is only supported on certain manufactures drives.

I am sorry this hasn't worked for everyone. For those that it has worked for GREAT, for those that it doesn't work for I'm sorry, but I have given all the information I have to give.

Good luck to all....

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The authors low-down
Authored by: bluehz on Jul 20, '02 06:16:55PM

Its not that we are not having some limited success - but only if we use Disk Copy to burn the initial session and all other session. I don't think many have had any success with starting the burn from the Finder as the initial session. Aslo _ doubt that it is an external/internal issue as the process works flawlessly using Disk Copy on both my internal and external drives. So the problematic area seems to be the Finder (or whatever underpinnings for IOServices that serve disk burning) in most case.

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The authors low-down
Authored by: macubergeek on Jun 12, '03 08:59:36AM

dude this hint does not work if the cd is burned from the finder initially

tried it every way from tuesday and IT JUST DOSN'T WORK

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Works from Disk Copy on external CD-RW
Authored by: rv8 on Jul 20, '02 10:50:35PM

I've got a Cube, running OS X 10.1.5, with a LaCie 24x external CD-RW. I tried this hint after burning a CD-R from the Finder - it didn't work. The Finder complained that the previously burned CD-R was unusable. Then I burned a fresh CD-R from Disk Copy. This time I was able to append a second session. Great! Thanks for the hint.

I also noted that the process of burning a CD-R from Disk Copy is quite a bit quicker than doing it from the Finder. The Finder goes though a long "Preparing Data..." process after you tell it to burn the CD, but Disk Copy starts burning right away.

I am very, very pleased to finally be able to do multi-session CDs. :):)

Kevin Horton

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Works from Disk Copy on external CD-RW
Authored by: joesim on Jul 21, '02 06:41:09PM

One suggestion/question?

Did you use the "Burn Disc" item in the Finder's "File" menu.

This will probably not work in the first place on an already burned CD. After the initial burn, leave the "Finder" out of ALL involvement in the burning proceedure.

JUST use "Disk Copy".

Just a thought.....!

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Nope, used Disk Copy for both second attempts
Authored by: rv8 on Aug 06, '02 08:36:00PM

I used Disk Copy for the second attempt in both tests.

Test 1 - Burn fresh CD-R from the Finder, then use Disk Copy to try to append a second session - didn't work.

Test 2 - Burn first session using Disk Copy, then use Disk Copy to append a second session. Worked great.

This is using an external CD-RW drive. Maybe I would get different results with an Apple internal CD-RW, but I don't have one of those to test.

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on PC?
Authored by: VEGx on Jul 21, '02 10:42:10AM

Can these CDs be read on a PC, and can they be appended by some (random) burning software on PC.

At times I have to take CDs with me to school and sometimes I need to burn files on CDs at school... as I sort of a lost my internet connection at home...

Has anyone tested this?

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Erase a multi-session CDRW
Authored by: jpcuzzourt on Jul 21, '02 05:23:12PM

After making a multisession disk (Using diskcopy only since that works for me), I can't get diskutility to erase the CDRW. It complains that the volume doesn't dismount properly. I suspect this is because the CD gets mounted as 2 or more volumes. Anybody duplicate this? Anybody successfully erase a CDRW?
Thanks for the Hint. Should work fine as is for CDR!

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Erase a multi-session CDRW
Authored by: jpcuzzourt on Jul 21, '02 06:09:18PM

I think I figured it out, somewhat. I can erase if I uncheck the Quick Erase option in Disk Utility.
When a quick erase is attempted, only the volume created by the first session gets unmounted.
Of course, doing a long erase takes a while on a 4X CDRW disc.

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Unmountable Disks
Authored by: joesim on Jul 21, '02 06:29:49PM

I have had this issue a few times, even when trying to erase HDs. I think it is more a limitation of the Automount/Unmount process of Mac OS X than a failing of "Disk Utility".

Try ejecting the CD, then re-inserting it. After insertion DO NOT open it or click on any of the icons. Go directly to "Disk Utility" and try erasing it. The problem is usually that the "Finder" thinks the disk is in use, and therefore won't let it unmount. You may want to try unmounting all but the first session burned to that CD in the "Finder", then seeing if "Disk Utility" will erase it.

Good luck, happy burning...

And thanks to the CUBE owner for testing this out since I haven't had time to yet...


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What kind of disk?
Authored by: mahakali on Sep 23, '02 06:45:11PM

Did you try this using a CD-R or a CD-ReWriteable (CD-RW)? Multi-sessions only work on CD-RW disks..

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