Installing older macOS says "unable to detect operating system"

Discussion in 'macOS Virtual Machine' started by Bobby7, Jan 4, 2022.

  1. Bobby7

    Bobby7 Bit poster

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    I have a MacBook Pro and I'm running Big Sur. I'd like to install either Yosemite or Sierra as a virtual machine. I downloaded the .dmg files but when I try to install them it says "unable to detect operating system." Customer support told me that I need to use an .app file, not a .dmg file. I tried searching for MacOS .app files but I can't find them. Does anyone know where to get them? Or is there a way I can use the .dmg file? Thanks.
     
  2. Maria@Parallels

    Maria@Parallels Problem solver

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    Hi, according to your comments, you've already found the solution. Could you share it here please? Maybe it will be helpful for other users.
     
  3. Bobby7

    Bobby7 Bit poster

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    Sure! I opened up the .dmg file and installed it. After it installed, it created an .app file in the applications folder. I used that .app file when creating a new macOS virtual machine in Parallels and it worked. Hope that helps anyone else who was having this problem!
     
  4. naveeds2

    naveeds2 Bit poster

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    Install macOS from Scratch ยท Apple Silicon (M1 chip and newer): Press and hold the power button until you see the startup options window,
     
  5. naveeds2

    naveeds2 Bit poster

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    If you try to install a macOS that is older than the version currently installed, the installer will say that it is too old to be opened on.
     
  6. Appsquadzllc

    Appsquadzllc Bit poster

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    it says "unable to detect operating system" then if ... r/mac - Just got me my first MacOS device after 16 years on PC.
     
  7. Space Club Vape

    Space Club Vape spaceclubextracts vapes

    Messages:
    1
    I have a MacBook Pro and I'm running Big Sur. I'd like to install either Yosemite or Sierra as a virtual machine. I downloaded the .dmg files but when I try to install them it says "unable to detect operating system.
     

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