"Unable to detect operating system" Guest OS macOS

Discussion in 'Installation and Configuration of Parallels Desktop' started by KeithR1, Apr 2, 2023.

  1. KeithR1

    KeithR1 Bit poster

    2018 MacBook Pro macOS Ventura 13.3
    Parallels Desktop v17.1.16
    Guest OS X Mountain Lion 10.8

    I have some legacy software that integrates with hardware. I need to run 10.8 or less.

    Parallels message "Unable to detect operating system" when I try to install OS X Mountain Lion 10.8. If I continue it still fails.

    I have download directly from Apple the InstallMacOSX.dmg multiple times.
    Mountain Lion 10.8

    In my research, I noticed this predates the Contents/SharedSupport/InstallESD.dmg layout of newer installers.

    The installers located in 'Packages' folder with Essentials.pkg being the largest at 1.8GB
  2. Pavel Merkulov

    Pavel Merkulov Parallels Team


    Thank you for your feedback.

    To let us better understand the situation, please perform the following steps:

    1. Run your virtual machine and reproduce the issue.

    2. Collect a technical report (click on the Parallels icon > Help > Send technical data > check "Attach screenshots..." > press Send Report) and send the report's 9-digit ID in a reply.

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