MP 1,1-5,1 cmp won't boot headless.

[Gnx231]

Good morning all. I have a 2010 cmp I have connected to my 2019 MP via ethernet cable. I was logging into the cmp using share screen. everything worked fine until a few weeks ago I started the cmp and nothing. I will only boot if I attach a monitor. I have done a pram restet and a smc reset and still nothing. It's running PCLP and it is on sequoia. Works fine other than this.

 

[panjandrum]

Generally speaking modern systems will not function properly without a monitor attached. You should have been getting a single resolution and no video acceleration IIRC (I haven't bothered trying in probably a decade now). What you can do is buy a headless monitor dummy / dongle / headless adaptor etc. I run about half a dozen headless Mac Pros with these things without any issues. They work great. (There are a variety of types and resolutions available, this is just an example.)

 

[Gnx231]

Hum. Why would it work fine and the all of the sudden not work?

 

[Gnx231]

Just ordered the dongle from the link you provided. Thank you.

 

[MarkC426]

Another option….
Connect your cMP to your monitor (as well as your 7.1), but leave the 7.1 as the input channel.
This will give you all the screen resolution options.