Four CD-ROMs.
Picture courtesy of Pixabay, under CC0.

Mounting Old Windows/Mac Hybrid CDs on Mac OS X

Daniel Malmer
3 min readJun 30, 2020


For the impatient, here’s the solution that worked for me:

mkdir ~/cdrom
sudo mount -t cd9660 /dev/disk2s1 ~/cdrom

I found an old CD from 2002 that had some files that I wanted to view. I was hopeful that when I inserted the disk that the drive would mount and the files would show up in Finder. Unfortunately, it wasn’t that simple.

The drive accepted the old CD, and I could hear some activity, but nothing showed up in Finder. The first thing I did was bring up the Disk Utility to see if the device was recognized at all.

Disk Utility clearly recognized that a CD had been inserted, and even was able to read the partitions. In spite of that, it wasn’t automatically mounting the CD.

According the Disk Utility, the Device was disk2, so I tried to mount /dev/disk2. I had to specify the filesystem type, so I took a guess that it was msdos.

sudo mount -t msdos /dev/disk2 ~/cdrommount_msdos: Unsupported sector size (0)
mount: /Users/malmer/cdrom failed with 71

My next step was to wander around the internet looking for solutions.

One webpage recommended that I see if Mac understood what filesystem was on the CD.

file -s /dev/disk2/dev/disk2: data

That wasn’t informative. I took at look at the various versions of mount to see if there were any other likely candidates.

ls /sbin/mount*/sbin/mount         /sbin/mount_cddafs  /sbin/mount_msdos
/sbin/mount_9p /sbin/mount_devfs /sbin/mount_nfs
/sbin/mount_acfs /sbin/mount_exfat /sbin/mount_ntfs
/sbin/mount_afp /sbin/mount_fdesc /sbin/mount_smbfs
/sbin/mount_apfs /sbin/mount_ftp /sbin/mount_udf
/sbin/mount_cd9660 /sbin/mount_hfs /sbin/mount_webdav

I tried exfat, because that’s another old Windows filesystem.

sudo mount -t exfat /dev/disk2 ~/cdrommount_exfat: /dev/disk2 on /Users/malmer/cdrom: Permission denied

I then searched the web for what formats were likely used for CDs from that era. ISO9660 and UDF were both candidates.

sudo mount -t cd9660 /dev/disk2 ~/cdrommount_cd9660: Invalid argument
mount: /Users/malmer/cdrom failed with 1
sudo mount -t udf /dev/disk2 ~/cdrommount_udf: /dev/disk2 on /Users/malmer/cdrom: Device not configured
mount: /Users/malmer/cdrom failed with 1

At this point, it finally occurred to me that maybe /dev/disk2 wasn’t exactly the right device.

ls /dev/disk2*/dev/disk2    /dev/disk2s1    /dev/disk2s1s1    /dev/disk2s1s2

If I’d looked a little more closely at the Disk Utility, I would have seen that in addition to disk2, it also mentioned disk2s1.

I tried mounting /dev/disk2s1, and that’s what did the trick.

sudo mount -t cd9660 /dev/disk2s1 ~/cdrom

I was able to copy the files. I then unmounted the CD.

sudo umount /dev/disk2s1

My final problem was that I wasn’t able to eject the CD. It didn’t show up in Finder. When I tried to eject it in Disk Utility, I got the message Failed to eject [disk name] because it is currently in use. I tried drutil tray eject, and it returned without doing anything. In order to eject the CD, I had to reboot my machine.

It’s not often that you need to read files from an old CD, but hopefully this will save somebody some time and frustration.



Daniel Malmer

PhD student researching online hate speech, extremism, and radicalization.