Can't Mount ISO Image on MacBook Pro (macOS Big Sur)

macos tips
1

I want to mount a macOS ISO 64-bit ISO on my MacBook Pro running macOS Big Sur,
but failed.
After double-clicking,
an error saying “not mountable” appears.
The system doesn’t allow me to mount it and alerts me that I don’t have permission.
What should I do?

2

If you don’t have permissions to mount it, right-click the file, select Get Info, move to the Sharing & Permissions section, click the bottom lock icon, enter your admin password, and then change your privilege to Read & Write.

Then, try to mount the macOS ISO file again.

3

How did you get this macOS ISO file? Your ISO file may be incorrectly structured or made for other platforms. Re-download it from this macOS ISO download database.

Or, you’d better create a macOS ISO file by yourself. This ensures you get an intact and safe ISO file.

Since macOS is compatible with macOS DMG files, you can download the DMG file first and then convert the DMG to ISO.

  1. Download iBoysoft DiskGeeker and launch it.
  2. Select Download Image on the left sidebar.
  3. Choose a desired macOS version and click Download Image.
  4. Wait for the macOS DMG file to be downloaded.
  5. Open Terminal from Launchpad > Other.
  6. Enter hdiutil convert and press a space.
  7. Drag and drop the macOS DMG file into the Terminal window.
  8. Press a space and type -format UDRW -o
  9. Type a space and copy and paste the path of the macOS DMG file and change .iso to .cdr.
    This is to save the converted .cdr file to the same destination as your ISO file.
  10. Rename the converted .cdr file’s extension - .cdr to .iso

Here, I give you an example of the intact command line:

hdiutil convert ~/Desktop/Catalina.dmg -format UDTO -o ~/Desktop/Catalina.cdr

1 Like
4

I think your ISO file is probably corrupted. You’d better re-download it.