MP 1,1-5,1 I have a problem starting up with other monitor: it isn't recognized.

[BelgianBoy]

I had to switch to an older monitor because my monitor is in repair. When starting up now it shows flashing alternatively the Apple logo and a ⊘ sign. Could the old video settings in System prefs be the cause? Is there a way I can force the Mac to recognise the monitor? I'm on an CMP 3.1 with Capitan.

 

[BelgianBoy]

Really nobody with an idea?

 

[ifrit05]

Boot with verbose mode on for more details about what's going on. A prohibited Apple logo shouldn't be caused by a monitor.

 

[BelgianBoy]

You mean cmd-R? I did that with no result: same logo/⊘
cmd-V is chinese to me...

 

[ifrit05]

No, cmd-v.

 

[BelgianBoy]

As I said: cmd-V is chinese to me... A am not versed in code.

 

[ifrit05]

Upload a screenshot, I may be able to diagnose for ya.

 

[BelgianBoy]

But your assesment is that it isn't the monitor? I only can make a photo since the mac is unresponsive. I suppose that is what you meant.

 

[ifrit05]

Do you have a smartphone/camera that you can take a picture with?

EDIT: Read that wrong. Yes, please take a photo of the text that appears when booting with cmd-v where it stops booting.

 

[BelgianBoy]

 

[ifrit05]

Seems like the bootloader cannot find the macOS kernel. Either your hard drive is corrupt/failing or your boot drive is not blessed properly. This is not something that can be caused by a monitor switch.

Hopefully you have a recent backup through Time Machine you can restore with. Since you cannot boot into recovery mode I would get a macOS installer USB then boot with that to start a Time Machine Restore.

EDIT: Might want to try a NVRAM reset and a SMC reset before doing a restore, it may fix the issue (I don't think it will).

Reset NVRAM on your Mac - Apple Support

If one or more settings stored in NVRAM don't work as expected on an Intel-based Mac, resetting NVRAM might help.

support.apple.com

Reset the SMC of your Mac - Apple Support

The SMC is responsible for managing power on your Mac. Resetting it can resolve certain uncommon issues related to power or thermal management.

support.apple.com

 

[BelgianBoy]

It's what I supected somehow. I'll post back when I get this resolved. Thks 4 the help !

 

[BelgianBoy]

I took the startup disc tray out and reseated it: hey presto, problem solved. It's like old school mechanics: if your car won't start, check the fuel first. Her it was old school electricity.