I have High Sierra installed from a USB bootable drive on a Samsung SSD (Samsung MZ-76E500B/EU 500 GB 860 EVO Sata III 64L V NAND Solid State Drive) but I need XCode and that needs to be on Mojave 10.14.4+ and because i have a third party SSD the app store blocks me from upgrading.

So I put a Catalina beta on a USB drive but when I load up the iMac holding option and select the drive I just get a cancel symbol.

Not sure what to do to get a more modern OS on this SSD? Anyone had any luck with Mojave or will that be the same?

Thanks in advance

  • 3
    What Mac do you have, precisely? I'm not sure why the App Store would deny the update just because you've got a 3rd party SSD. All the Macs here have 3rd part SSDs & each is updated as far as its model will allow.
    – Tetsujin
    Commented Oct 5, 2019 at 10:04
  • do you have less storage? you can try downloading the compressed file from Apple Developer Website but it doesnt make it easier for you to install if there's no space. (notify me by @ankii)
    – anki
    Commented Oct 5, 2019 at 20:48

1 Answer 1


It would appear the issue is with compatibility, it is a Mid-2011 27 iMac so no longer supports Mojave or Catalina



  • 1
    You could try macOS Mojave Patcher Tool for Unsupported Macs but note the comment "iMac12,x (systems with AMD Radeon HD 5xxx and 6xxx series GPUs will be almost unusable when running Mojave."
    – lx07
    Commented Oct 5, 2019 at 11:29
  • 1
    The only other options I can think of are, get a new Mac, or create a Mojave/Catalina virtual machine and run Xcode in it.
    – user128998
    Commented Oct 5, 2019 at 12:29

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