iMac 2011 not starting in High Sierra (safe boot works)

iMac 21.5-inch, Mid 2011

2,5 GHz Intel Core i5, 4 GB 1333hz DDR3, AMD Radeon HD 6750M 512MB

I bought a used iMac 2011 without a hard drive about 4 days ago.

I replaced the HDD with a 500gb that I had lying around.

Had some problems installing macOS Lion through the online recovery. (something like can't prepare installation).

Installed macOS Lion through an USB. updated to Sierra with the installer update, then to High Sierra through the App Store.


In every macOS (Lion, Sierra and High Sierra), it can't start without safe boot.

I only tried verbose mode in Sierra and High Sierra and the last thing I logged in was: "IOConsoleUsers gIOScreenLockState 3".


I don't know if it's important, but some lines before that it wrote "Unsupported CPU" two times and "Unsupported PCH".


How can I fix this?

Thanks to everyone that's trying to help me

Earlier Mac models

Posted on Jul 24, 2023 10:59 AM

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iMac 2011 not starting in High Sierra (safe boot works)

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