HDMI Problem since El Capitan

Question

HDMI Problem since El Capitan

Configuration:

1. Mac Mini late 2014

2. Windows PC (Windows 10)

3. HDMI Monitor Switch with power supply to switch between the Windows PC and Mac Mini

This configuration, which worked well with Yoshemite, seems to corrupt the Mac system.

The Mac doesn´t accept the switch and breaks down and I need to reinstall El Capitan.

CMD/R works, but does not fix the Problem.

Other commands don´t work.

I tried a switch without power supply and if I first start the Windows PC and then the Mac, everyting works fine.

I can switch between both computers, but it doesn´t work, when I first start the Mac and then the Windows PC

The Mac does not recognize/accept the switch (black Screen).

Using the monitor switch without power supply and when switching off the Windows PC, the Mac screen is switched off as well.

There is no way to reactivate the Mac video signal,

Using the monitor switch without power supply when I restart the Windows PC and then again the MAC everything works fine again, whereas using the monitor switch with power supply results in a dead Mac.

Posted on Oct 8, 2015 1:37 AM

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Answer 1

Best reply

lllaass

Level 10

210,411 points

Oct 9, 2015 5:59 AM in response to peterfromlichtenau

Did you have to install any software of the Mac?

- Try resetting the SMC and NVRAM/PRAM

Intel-based Macs: Resetting the System Management Controller (SMC)

About NVRAM and PRAM

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Answer 2

Oct 9, 2015 6:06 AM in response to peterfromlichtenau

Sorry the problem is not solved.

No additional software installed. Neither of them worked. The mac only reacts to CMD/R.

I thought I solved the Problem by no longer using the Monitor, but after I restarted the MAC the next day directly conected to the monitor, it hanged again.

I guess I have to reinstall Yosemite again, but have no idea how to get to Yosemite, because I have no Yosemite backup.

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