Strange Airplay problem

[neilf]

Using all the latest and up to date software.
iTunes running on a 2010 Macbook Pro and I can see all my Airplay devices when I select the "multiple" dropdown list.
But when I select any of those devices, the Audio/video only plays on the Macbook Pro whether it is selected or not.
Other manufacturer's apps seem happy to connect to any of my Airplay devices, but the Apple software refuses to connect to anything except the computer the iTunes library is running on.
I hope this makes some sort of sense. Has anyone any ideas please?

 

[chscag]

I'm certainly not an expert on Airplay, but it appears your 2010 MacBook Pro does not meet the requirements to use Airplay:

Requirements for using AirPlay

If you go to Apple menu > System Preferences, click Displays, and don't see the option to "Show mirroring options in the menu bar when available," your Mac doesn't meet these requirements.
Minimum requirements if your Mac and Apple TV are on the same network:
Apple TV (2nd generation or later) with the latest Apple TV software
For mirroring your display or extending your desktop, any of the following Mac computers with OS X Mountain Lion v10.8 or later:
iMac (Mid 2011 or later)
Mac mini (Mid 2011 or later)
MacBook (Early 2015 or later)
MacBook Air (Mid 2011 or later)
MacBook Pro (Early 2011 or later)

 

[neilf]

Sorry. My mistake. I mentioned video. It is only audio, and all I am doing is using iTunes to connect to remote speakers. Whether that be an Apple TV or my Denon amp. It has been working fine up until yesterday.
I haven't tried this yet, but I was thinking of deleting the iTunes plists. Although , I keep my iTunes library on a NAS, so that either my Macbook Pro or my Mac Mini can use it. So I'm not sure if deleting the plists will make any difference.

 

[chscag]

Go ahead and give that a try. in the meantime have you changed anything like hardware or done any updating?

 

[neilf]

I am confused now!!
I tried iTunes Airplay tonight, and it's now working.
I have made no changes to anything since I posted this query, so how is it that it now works, whereas it didn't work yesterday? Malware? Virus?
So, thanks for the interest, and I hope it keeps working.