I recently got a new iMac running Sierra. I'm trying to find a way to play an old game from the 90s that I used to love called Jump Start 4th Grade Haunted Island. I have the CD, but I no longer have the computer it ran on. It won't work with anything later than Mac OS 9. I was able to install SheepShaver with OS 9 and it works, but whatever I try, I can't get the disk to mount. I've tried ISO, DMG, IMG and other formats but I keep getting errors. Is there a way to get around it?
Any help would be enormously appreciated!

You do not write exactly how you tried to mount the image in SheepShaver.

Any format should work, as long as it is in a read/write format. The image file should then be locked in the Sierra Finder to convince the software that it is on a (read-only) CD.

Best try an image created in Disk Utility in DVD/CD Master (.cdr) format.

Add the image file to the volumes list in SheepShaver preferences, then quit and start again SheepShaver. Make sure the image is NOT mounted in Sierra.

Macintosh Garden has an .iso disk image of this game for download. It can be mounted fine in both SheepShaver and BasiliskII on my Sierra machine. As the game is 68k, you may also want to try it in BasiliskII.

Thank you so much for taking the time to respond!
I checked out Macintosh Garden and unfortunately that's a different version of the game (Sapphire Falls). I do have an ISO of Jump Start Haunted Island and I locked it in Sierra as you suggest. I copied it to SheepShaver and used Virtual CD manager to "Create CD/DVD Toast image", but I still can't open it as an actual CD. Then I tried adding the ISO to the volumes list in SheepShaver but that seems to have failed too. I keep getting the message "Background script error: Finder got an error: Can't get alias "Unix:SendToMacOS9". Then it just goes into total meltdown and keeps flashing the message until I force quit SheepShaver. Should I copy the ISO to the Mac OS 9 desktop first?
I know I'm missing something major and apologize for my stupidity. I just don't know how to do it correctly. Thanks in advance!

I do not know why your .iso file cannot be mounted the regular way.

Maybe start over. Create a .cdr image from the CD-ROM using Disk Utility. Add that file to the volumes list in SheepShaver prefs.

Using the Virtual DVD-ROM/CD Utility (or VirtualCD Imager, it is referred to by several names) is a next step and only when needed.

Tried it again, folllowing the steps you suggest. Still no luck. Keep getting the same message: "Background script error: Finder got an error: Can't get alias "Unix:SendToMacOS9". Not sure what that means.
I copied the .cdr to the Mac OS 9 desktop in SheepShaver and used Disc Copy to mount it. It looked like it mount successfully, but when I tried to open it, it said "disc error." I'm probably missing something but I don't know what it is.

Maybe you didn't check Macintosh Garden thoroughly enough. Isn't this the game you want:
http://macintoshgarden.org/games/jumpst ... ted-island
This .iso mounts fine in SheepShaver.

You're absolutely right, that is the game I was looking for! Thank you. To my great frustration, however, when I tried to mount it I got the same error I've been getting - "Background script error: Finder got an error: Can't get alias "Unix:SendToMacOS9". I still don't understand what it means and every time it happens I have to force quit SheepShaver to make it go away. I can't figure out what could be causing this.

Are you adding the iso on your host in the SheepShaver preferences and rebooting, or are you trying to open the iso through the Unix folder on the guest OS? The error sounds like the second.

Thanks for you reply! No, I'm trying to add the ISO in Preferences and reboot, but I get the error message the instant I save my Preferences. Then when I manage to reboot, the ISO vanishes from Preferences.

Please post here the content of your prefs file:

Open Terminal (in /Applications/Utilities/)
Type at the prompt followed by a return.

The prefs file will open in your default text editor. Select all content, copy and paste it here in your reply.

Edit:
Do you keep the iso in the shared folder and is there an alias in the path you enter to the iso file?

No, I keep the iso on my regular desktop and I don't think there's an alias.

This is what I got from the prefs file:

extfs /
windowmodes 0
screenmodes 0
serialb /dev/null
bootdrive 0
bootdriver 0
ramsize 16777216
frameskip 8
gfxaccel true
nocdrom false
nonet false
nosound false
nogui false
noclipconversion false
ignoresegv false
ignoreillegal false
jit true
jit68k false
keyboardtype 5
keycodes false
mousewheelmode 1
mousewheellines 3
dsp /dev/dsp
mixer /dev/mixer
ignoresegv false
idlewait true

I see only default values and no further configuration. I do not see any volume, not even a MacOS startup volume.
In your first post you wrote: How can that be without an OS9 disk?

Could it be that you do not use a regular SheepShaver installation, maybe a SheepShaver virtual machine, or maybe some other pre-configured SheepShaver setup that does not use this prefs file in your Home folder?

This indicates you are running the SheepShaver wrapper from this page: http://www.columbia.edu/~em36/sheepshaverwrapper.html Correct?

Perhaps reinstall? Anyway, questions about such installations should go into the "Other SheepShaver configurations" subforum: viewforum.php?f=33

Best,
Cat_7

Thanks! That's exactly where I got it. I apologize again for my ignorance, but is that a bad thing? Is that why I can't get the iso to work?
I tried to reinstall but nothing changed. Thanks again to everyone who responded, I really appreciate your time and advice. I'll try the "Other SheepShaver configurations" subforum if that's what you suggest.

@Yorwick, and anyone else who (like me) came across this thread:

I hit similar problems and eventually found a solution that worked for me.

1. Download the ~620MB bundle from http://www.columbia.edu/~em36/macos9osx.html and expand it (let's call this "Application A"). Problem: When trying to run this on High Sierra 10.13.6, I got a message
   Code:
   "Mac OS 9.app" is damaged and can't be opened.  You should move it to the Trash.
2. Download the SheepShaver wrapper from http://www.columbia.edu/~em36/sheepshaverwrapper.html and expand it. Let's call this "Application B". Problem: I don't have a Mac OS 9 install CD to hand, so can't follow all of the remaining suggested steps.
3. Solution: Combine the two!

Note that ordering is important in the steps below.

1. Move Application B to the Applications folder.
2. Drag the
   Code:
   Mac OS ROM
   on to Application B as per the instructions in (2) above.
3. In two windows, right-click each Application and click "Show package contents". From Application A, copy Contents/Resources/Files/MacOS.sheepvm to the same location in Application B (this should be replacing a ~54MB file with a ~1.25GB one). After this you no longer need Application A.
4. Double-click Application B. Once Mac OS 9 starts, you'll see the errors like "File Unix:SendToMacOS9 wasn't found" as per previous comments in this thread.
5. Open a Finder window, and then click File->Find. Search for MacOS9BackgroundScript (just in the MacOS9 drive, not Unix). Delete or move both files.
6. Shut down the emulator using the Apple menu, and then open Application B again. Hey presto, no more annoying background script errors, and you have a working Mac OS 9 VM.

Hope this is useful to anybody who finds it.