
Dec 15, '11 07:30:00AM • Contributed by: squalene
When a connectivity issue like that happens, the Finder is supposed to alert you with a 'Connections interrupted' dialog that gives you the opportunity to disconnect. However, it's a small dialog, and sometimes goes away by itself when perhaps it shouldn't.
If I miss the dialog, or click ignore, and leave that unavailable server on my desktop, any application that does a sloppy job of asking for information on mounted partitions can cause the Finder to hang.
That leaves Finder menu items such as 'Restart' or 'System Preferences' unavailable. The Apple Menu's 'Force Quit' keyboard shortcut still works, but often the unresponsive Finder will simply quit and never restart.
Fortunately, the Wi-Fi Menu on the right side of the Menu bar still works. You turn this on using the Network System Preferences pane.
Turns out that using that to turn off Wi-Fi, then waiting for a bit, and turning Wi-Fi back on clears the Finder's beachball, removes the old Mac from network visibility, and pretty much returns all functionality to normal.
There are lots of ways besides having an old Mac hooked to a network that could cause parts of a home network to become unresponsive. Toggling the Wi-Fi network connection can probably fix a lot of the problems they cause too.
If you want to see what happens to Lion's Finder when Wi-Fi becomes unresponsive, try turning off Wi-Fi from the Menu. As you try to use Apps normally, sooner, rather than later, you'll end up with a whirling beachball in the Finder, your Apps, etc.
[crarko adds: A lot of Finder related hangs are certainly due to Network errors that don't timeout in a reasonable period, based on my experience. Not all of them are, though, so this isn't a cure for all cases of the Beachball of Death, but it will handle a number of them. Note that in some cases the SystemUIServer (which handles menu extras like the Airport menu) will also hang, preventing access to the menu item. Then you're pretty much stuck with a hard reboot.]