It sounds like something it seriously wrong. First, try toggling the scan mode from passive to active and back – perhaps the preference was corrupted. If that does not change the situation then please try deleting and reinstalling the application. We have tested IP Scanner on hundreds of networks, some with 100s of devices so we know this is an anomalous situation.

On the Mac, that option is in the Preferences, accessible from the main app menu (next to the Apple logo at the upper left of the screen).

On iOS, you need to tap the 'Tools' button at the lower right of the screen to access the scan style toggle.

ah yes, I see that on the Mac it is called 'show hidden devices' in the Prefs. Tick that box (or if already ticked, uncheck and the check it again to reset it).

Of course the missing device could also live on a different subnetwork from the machine doing the scanning (ie the main subnet is 10.0.0.x whereas the missing device is on 192.168.1.x, for example), in which case IP Scanner would only be able to find it if you add that extra sub network as a custom scan range.

some Windows versions do not respond to Ping by design, which could be why the dot is not showing…but this is a good question, and we'll add an FAQ to explain better what that dot is.