AirDrop is a feature that was introduced in OS X Lion that enables you to easily transfer files to other Mac users around you. Open a Finder window, click AirDrop in the sidebar on the left and you'll see other Macs within Wi-Fi range that are also using AirDrop. It's then a simple matter of dragging a file and dropping it on a Mac to transfer it. The trouble is that no Mac older than 2008 is supported and few older than 2010 are supported. However, there is a way to make AirDrop work on all Macs.
This is the official list of Macs that can use AirDrop:
I'm using it on a 2006 white MacBook and it works just fine.
The reason why it doesn't work on older Macs is because of the way it works. AirDrop tries to establish a network connection directly between Macs. The Macs don't need to be connected to a Wi-Fi or wired network or the internet. Even with no network at all, they can connect. It's a sort of ad-hoc network created between the Macs. Macs could even be on different Wi-Fi networks and still connect because it's not used.
The snag is that this direct connection between Macs only seems to work with certain Wi-Fi chipsets. It is possible to configure AirDrop to create a connection over the current wireless network instead of creating one itself. This means that any Mac (running Lion of course), can use AirDrop. The drawback is that they have to be on the same wireless network. It's actually not much of a limitation though.
Go to the Utilities folder and run Terminal. At the command prompt enter:
defaults write com.apple.NetworkBrowser BrowseAllInterfaces 1
Restart the Mac and you can now use AirDrop. It sort of works if you just enter the command on one Mac, but it is better if you do this on all your Macs. That way they are all using the same system.
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