Apple display does not allow icc profiles. Images printing very dark.

You should always test output using good color reference images designed for that task. The color reference images' RGB values are such that they are set for output and are editing and display agnostic. Test the output this way and examine for the same color issues so we know it's not your image-specific issues causing the problems:
http://www.digitaldog.net/files/2014PrinterTestFileFlat.tif.zip

I did some searching and found a video on YouTube by ArtisRight - Apple Studio Display Calibrite / X-Rite Full Calibration Guide that provides a solution. Although the software is pretty recent, my X-Rite ColorMunki calibration device, itself, is at least 8 years old, not the more recent and more expensive X-Rite Calibrite device he used for the demonstration. There was more data and information he was able to get that I can’t get. But, my device worked. Unfortunately, with the new display you can’t simply determine and apply icc profiles like we did with the older displays. Everything now is done with “Presets”. I think at times, Apple makes things a lot more difficult and frustrating rather than making things easier and better!!!

But, following his directions, I was able to adjust the settings within the Presets in Display and almost completely resolve the issue. Now that I know what I am doing, I can try making other adjustments to do some fine-tuning. I could also spend some time re-doing the calibrations and maybe the results will be even better. I will also do some more investigating to see if I could really benefit from one of the newer, more expensive models of Calibrite. I don’t think it’s so much the hardware, but the software that comes with the more expensive models. I do enough printing that it would probably be a good investment.

Sadly, I also saw a comment online that a BenQ display is a much better choice than the Apple Display when you intend to print! If that is true, I could have gotten the high quality BenQ photographer version for the same price I paid for the Apple! Kind of late now!

Thanks for the quick response.

By the way - did you take any steps to install the ICC profiles you wanted on the new computer? Or were you just hoping they would be there? What profiles were they?

Are you working with old images, tried and tested on the old Mac and monitor, also showing OK on the screen of the new system but printing too dark?

Or are you working with new images, made to look good on the new monitor but printing darker than the screen?