[SOLVED] Desperate need of help!! Black screen after boot

[Gmtech79]

Hi, hope someone can help me with this, about to lose my mind.
Have been running El Capitan since release on my system flawlessly. Figured I would update to Sierra but has been a headache.
Was able to upgrade ok to sierra by usb, app store update just kept reloading el capitan.
My problem is after the apple logo boot screen I just get a black screen on both of my monitors and they enter power save state. However I can connect remotely with my macbook pro and everything works. I have been searching but the posts I have found have been more for later model imac's where as my system def is imac 12,1 2012. Should I try imac 14,1? I hate to do that as imessage works now. I have a nvidia 640 (I believe, forget will have to check at lunch, been awhile since I have done any updates) I never needed the nvidia drivers for 10.11 but i did download and install them for 10.12 but did not help, so i uninstalled them. I have tried GraphicsEnabler=YES/NO, , with no change. Also have intergrated graphics disabled in bios with PEG set to load first.
I have a spare SSD that I am thinking of doing a fresh install on if anyone thinks that may help. I also have been using latest bulid of clover.
Please help, if there is anything I left out please help. I really need to get this thing up and running. Sorry for long post.
Thank you

 

[Gmtech79]

Ok sorry. It's a gtx 650. No change after fresh install. Integrated graphics work but stuck at low resolution. So now I need to figure out how to get my graphics card to work

 

[fxe74]

Ok sorry. It's a gtx 650. No change after fresh install. Integrated graphics work but stuck at low resolution. So now I need to figure out how to get my graphics card to work

I have the same mobo,cpu and graphics card as you. I also had the same exact problem as you. Then I changed my system to 14,2 and it now works.

 

[Gmtech79]

I have the same mobo,cpu and graphics card as you. I also had the same exact problem as you. Then I changed my system to 14,2 and it now works.

All you did was change to 14,2 in config.plist and nothing else? And imessage and all icloud works? Or will I need to generate all new serials and other numbers?

 

[fxe74]

All you did was change to 14,2 in config.plist and nothing else? And imessage and all icloud works? Or will I need to generate all new serials and other numbers?

I just generated all new numbers and changed to 14,2 and no longer had a black screen. I don't use imessage but icloud works fine.

 

[Gmtech79]

Great! Thanks will give a try.

 

[Gmtech79]

Dang! Changing to iMac 14,1 didn't do anything. Unless, do you have inject Nvidia enabled in your config.plist?

 

[Gmtech79]

Anyone have any ideas? Would waiting until the first 10.12 update help?

 

[fxe74]

Dang! Changing to iMac 14,1 didn't do anything. Unless, do you have inject Nvidia enabled in your config.plist?

I have mine as 14,2 not 14,1. Yes, inject nvidia.

 

[VioletDragon]

Dang! Changing to iMac 14,1 didn't do anything. Unless, do you have inject Nvidia enabled in your config.plist?

GTX 650 is native. No need to have (inject nvidia set to true). It needs to be false.