APEndpointAggregate Message

Also, you might take a look at this: Combine multiple audio interfaces by creating an Aggregate Device - Apple Support

I just checked that setup on my wife's laptop and nothing weird was there (no Aggregate devices) but it possible that some bug has been triggered between Airplay devices and these fairly arcane MIDI device setups.

Also google "airplay endpoint aggregate" and there is a lot of discussion on setting up disparate speakers to act as one aggregate device. I'm thinking this is related.

I've turned off airplay on the 2 older apple tvs in my house as no one was using them as such anyways. I'll update if the errors go away or persist.

My wife’s 2017 MBP has been throwing this same error repeatedly over the last few weeks. When it pops up you have to dismiss it 4 to 5 times as it repeats the error dialog. I tried a few things. It seems related to airplay audio as that dialog box with the speaker icon is the same as when Airplay pops up login dialogs. I have 3 Apple TVs in the House, 2 older and one newer one. Try airplaying audio to your Apple TV connected TVs or airplay speakers. It might just be related to local WiFi availability of them.....I’m still working on it and will update if my messing about has fixed it.

edit: it just occurred to me that APEndpointAggregate is probably referring to “Airplay endpoint.....”

You might want to consider starting a new discussion. Since this one is marked solved, less people are likely to look at it. A new post would be much more visible. You can link to this one.

Post in the High Sierra community.

macOS High Sierra

I wasn't sure what community to attach to, so I thought that the OS X would be appropriate. This choices are seriously out of date. I can pick up to Yosemite, but I am running 10.13.3 High Sierra. The keeper of the communities should add some of the newer OS choices.

I don't know what you were doing but the forums are quite up to date including a High Sierra forum. If you do a net search for "APEndpointAggregate in os x" you will find some information. Don't know if it is relevant to your problem.

After disabling Airplay on the two older Apple TVs (leaving Airplay enabled on the latest gen one) this error has not resurfaced. This isn't a fix but maybe a workaround?

For anyone else troubleshooting this, I should note some details about my set up. I have an Airport Extreme base station that my iMac is connected to by both ethernet and wifi. The iMac has never shown the APEndpoint error. The wifi is extended throughout the house by two Airport expresses in Bridge mode and the three Apple TVs are variously connected to that wifi as is the Wife's MBP. All three Apple TVs were accessible to any device on the wifi network.

I got rid of that annoying message, at least I think I have. I noticed the references to airplay and remembered I had recently swapped out my airport expresses with chrome cast audio devices. Since the airport express are no longer in use, I thought it would be interesting to see what is popping up in the Airport Utility. I noticed both old devices were showing an error symbol so I clicked on "Forget this Device" for each and voila, no more annoying messages. Give this a try. Cheers.

Question: Why does Apple give us messages which no one can comprehend? How about writing in plain English:

What does "Could not connect to "APEndpointAggregate" mean????

This is very annoying. Don't the programmers know how to write so anyone can understand? It used to be that Apple was the easiest to use since so much was self evident but is increasingly becoming less so.

Using Activity Monitor, I terminated the process named something much like "AirPlay UI Assistant" and it closed the error box.

what is APEendpointaggregate. how do i stop it from popping up.

This message started to appear in my MPB 2014 with High Sierra as soon I disconnected my new AirPods, following its first connection to the Mac.

yes started since updated my 2012 mac mini to osx 10.13.4 High Sierra, any ideas?