Can another computer use my iMac display?

Some year models iMac’s could be used by certain other year model Mac’s, but the list is small.

please carefully read > https://support.apple.com/en-us/HT204592

Thank you. But let me make sure my question is clear.

Your question would be clearer if you added the sub-model of the iMac (the part with a year) and what kind of computer you wish to be the source of the video signal. Currently people here are having to generalize. Two facts:

1) What you want an iMac to do is not supported for non-Apple products.

2) The ONLY iMacs supported as being an external monitor for another Mac were made between Mid 2009-2010 (27-inch only) and Mid 2011 - Mid 2014 (21.5- and 27-inch).

The rush to get "work-at-home" articles on the internet during COVID resulted on thousands of articles about iMac as monitors written without benefit of an editor or even proper research. That has led thousands here looking for something that does not exist.

MrHoffman wrote:

For those wondering, the clue here was “4K”. No Retina-class iMac can be a display.

Well, we tried. :)

For those wondering, the clue here was “4K”. No Retina-class iMac can be a display.

Nope.

r--ch313O7 wrote:

Thank you. But let me make sure my question is clear. Can I plug another computer into the iMac and access just the display?

You're welcome. Your question was clear. The answer is the same.

Those equipment profiles are wrong so often I've grown to distrust them.