I recently installed MacOS 9.0.4 so I could run my Tomb Raider 1 through 5 games as well as my Real Myst game. However, creating disk image '.cdr' files for each of these games via Disc Utility 1511.3.1 in El Capitan (Mac OS 10.11.6) appears to be not compatible with SheepShaver 20140201. After adding one of these .cdr image files in the SheepShaver volumes window, saving and then restarting SheepShaver, said image files do not appear on the MacOS 9.0.4 desktop. Instead, MacOS 9.0.4 'sees' an "Untitled" disk (which it states is "unreadable") and refuses to mount these disc images and only wants to initialize them. BUT -- all of my other disk '.cdr' image files that were created with Yosemite's earlier Disc Utility app work normally! Could someone please tell this newbie what is going on here and how I can get around this particular problem? A step-by-step guide would be greatly appreciated (feel free to send me a PM). Thanks in advance.

Computer: Mac Mini (Late 2014)
Mac OS: El Capitan (10.11.6)
CPU: 3 GHz Intel Core i7
Memory: 16 GB 1600 MHz DDR3
GPU: Intel Iris 1536 MB

I don't think it makes a difference whether the .cdr images are created in Disk Utility in Yosemite or El Capitan. The problem could be the format of these CDs. You can try to again create a .cdr image from a CD that worked before. If that image can be mounted in SheepShaver, the problem is not with the version of Disk Utility.

A bit off topic, but for creating images of Mac CD or DVD originals, many have found IMGBurn to be the most simple and reliable solution. http://macintoshgarden.org/apps/imgburn-250
If you don´t own a Windows box, the app runs fine e.g. in VirtualBox with a Windows 2000 guest.

IIRC it also runs inside WineSkin on OS X.

Thank you very much for your all of your reply posts, gentlemen!

Ronald P. Regensburg:

I made a disc image file just now with Disk Utility 1511.3.1 from a CD-ROM game that had mounted in SheepShaver before via Yosemite's Disk Utility and its created image file. And now this new image 'cdr' file won't mount and is "unreadable" -- so it sure seems to be this particular version of Disk Utility in El Capitan that is at issue here. There is a hack for loading Yosemite's Disk Utility back onto the El Capitan OS, but I'm rather leery of doing this on my Mac Mini.

24bit:

I downloaded IMGBurn and installed it and then ran it on my VirtualBox 5.1.26 (with Windows XP Pro SP3 as a guest - it's all I've got) and IMGBurn refuses to make a full disk image of a 600MB CD-ROM -- all it does is create a 45MB iso file (???) of this particular CD-ROM game.

CONCLUSION: This looks like a job for the Mac Doctor and so I'm going to call him right now!

UPDATE: Well, the Mac Doctor was far too busy and so I went with the risky move of executing the Yosemite Disk Utility (version 13) on El Capitan hack upon my Mac Mini .... and it worked! So all of my newly created cdr image files for my Tomb Raider and Real Myst games mounted just fine within SheepShaver (running Mac OS 9.0.4). Unfortunately, none of these games will run properly and TR3 actually crashed the SheepShaver app. -- oh my!

In short, all of that trouble for nothing!

Sorry to hear about your game trouble.
Could you verify that the games in question do work on a MPC 603 Mac at all?
Games for a G3 (MPC 750) or better will not work in SheepShaver by design.
G3 and later Macs also had dedicated graphics chips which SheepShaver does not emulate.
I don´t think any emulator around will do that - maybe QEMU will, some day.
You might try 10.5 Leopard in VMWare, just to have checked that too.
Rosetta in 10.5 and 10.6 makes a lot of apps work on Intel cpus, games will possibly be to demanding, graphics wise.
Send me a PM please, if you want to proceed that way.

As for IMGBurn, XP is fine of course, i was thinking of W2K as its the last one working without "activation" afaik. W2K is floating around on the net too.
Anyway, IMGBurn will offer creating a ISO file of many CD/DVDs, the size will be usually less than the total source capacity, free sectors are skipped for the ISO.
If the source is of mixed mode nature, a bin/cue file is the only option IMBurn will offer.

Indeed -- and I can attest to all that you've said here about my games from the G3 to G5 Mac era absolutely NOT working in SheepShaver because of my recent 'scientific experiments' to get Tomb Raider 1-5 and Real Myst to run in this emulator on my Mac Mini.

Even though I feel real silly now about even attempting any of this (I should've known better, but I'm a newbie), I really appreciate your feedback, 24bit. I fully realize that I'm just going to have to buckle down and spend the money that will be needed for getting my dual-boot G4 MDD completely 'resuscitated.' Thanks again for your advice!

Just as a word of warning: I recently tried running the original Nanosaur on my G4 OS X 10.4.11/9.2.2 Classic machine, and found that the required graphics acceleration wouldn't work through Classic. So you'll definitely have to dual boot to get some of those games from that era to run. I may have to get a machine again that can boot to OS 9, as I've still got a chunk of software I just can't run anymore.