If you try to start up your Mac from a hard disk, network volume, or Time Machine backup that contains an incompatible version or build of macOS, you might experience one or more of these symptoms:
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Testing conducted by Apple in July 2020 using preproduction 3.6GHz 10-core Intel Core i9-based 27‑inch iMac systems with Radeon Pro 5700 XT graphics with 16GB of GDDR6, 128GB of RAM, and 8TB SSD, and shipping 3.6GHz 8-core Intel Core i9-based 27‑inch iMac systems with Radeon Pro Vega 48 graphics with 8GB HBM2, 64GB of RAM, and 2TB SSD. Mar 30, 2019. Apr 17, 2020. Mar 18, 2020.
- Your Mac doesn't finish starting up, or displays a prohibitory symbol at startup.
- You see a message that you're using an unsupported or incorrect version of the Mac operating system.
- Your Mac doesn't respond to your trackpad, mouse, or keyboard.
- Apps unexpectedly quit.
- Your Mac doesn't sleep or wake.
- You don't hear any sound from your Mac.
- The fans in your Mac are louder, because they're spinning faster.
- The image on your display appears to shrink, has black bars around it, or appears tinted.
- You can't use Bluetooth or Wi-Fi.
Best Imac Configuration
Which Mac operating systems are compatible?
Best Imac Accessories
The version of macOS that came with your Mac is the earliest version compatible with that Mac. To find out whether your Mac is compatible with a later version of macOS, check the system requirements:
If your Mac won't start up from a compatible version of macOS, it might require a specific build of that version. To get the correct build, reinstall macOS or upgrade to a later version of macOS.
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Best Imac Hub
- To restore a Time Machine backup that was created on a different Mac, use Migration Assistant.
