iMac AirDrop not available when asleep, unlike MacBook Pro

On the laptop, there is a setting "Wake up for network access", in System Settings->Battery.

Clicking on Options... at the bottom reveals it.

I have just confirmed that it is relevant for using AirDrop. I set it to "Always" and was able to see the laptop as an AirDrop destination, even when asleep. I changed it to "Only on Power Adapter", put the Mac asleep on battery and it no longer shows.

Now the iMac does not have a battery, of course, but probably it has a "Wake up for network access" setting somewhere. I don't have an iMac but will try to check in a Mac Studio at the office to see if I can find it.

Dannymac22 wrote:

I have toggled "everyone". No luck. Also, I don't use VPN or third party security software. Now, there really isn't a "connectivity" issue per se. If the display is enabled on the iMac, AirDrop sees it just fine. If the display is off, it doesn't. The issue is that the display on the MBP does NOT need to be enabled in order for AirDrop to see it.

you can try making changes—

Change Energy settings on a Mac desktop computer - Apple Support

To be proactive you can file a bug report / submit your feedback here: Feedback - macOS - Apple  

Ok... a quick search says that (as I suspected) the relevant setting on an iMac is called "Energy".

See

Change Energy settings on a Mac desktop computer - Apple Support (CA)

Dannymac22 wrote:

Thank you, but that's not it. On my iMac, "Wake for network access" is turned on.

Verify your settings

also Airdrop issues ― toggle Everyone and compare you results

ref:

problems with communications between devices on the same network this includes Airdrop, and other Continuity features

If your device has network connectivity issues, check for VPN and other third-party security software. Uninstall.

ref: If your device has network connectivity issues, check for VPN and other third-party security software - Apple Support