@ianperrin I am able to reproduce quite often, but it is seemingly running normally?
i had several of these happen just now:
MMM-NetworkScanner received SCAN_NETWORK
MMM-NetworkScanner is performing arp-scan
Whoops! There was an uncaught exception...
TypeError: Cannot read property 'network' of undefined
at Class.scanNetworkMAC (/home/pi/MagicMirror/modules/MMM-NetworkScanner/node_helper.js:42:36)
at Class.socketNotificationReceived (/home/pi/MagicMirror/modules/MMM-NetworkScanner/node_helper.js:30:18)
at Socket.<anonymous> (/home/pi/MagicMirror/modules/node_modules/node_helper/index.js:113:11)
at emitTwo (events.js:126:13)
at Socket.emit (events.js:214:7)
at /home/pi/MagicMirror/node_modules/socket.io/lib/socket.js:528:12
at _combinedTickCallback (internal/process/next_tick.js:132:7)
at process._tickCallback (internal/process/next_tick.js:181:9)
MagicMirror will not quit, but it might be a good idea to check why this happened. Maybe no internet connection?
If you think this really is an issue, please open an issue on GitHub: https://github.com/MichMich/MagicMirror/issues