the iMac will not see anything via airdrop, the macBook see's everything, tried changing settings on iMac and still nothing, one is running High Sierra the other Catalina, any ideas ??
It is likely not High Sierra/Catalina but the hardware in the Mac running High Sierra.
Macs older than about 2012 cannot use the new (Improved?) AirDrop. Previous to Catalina, you could put newer Macs into Legacy mode to AirDrop with older Macs. That capability doesn't exist in Catalina.
iMac High Sierra and macBook Pro Catalina will not share anything via AirDrop, ideas ??
