What app used my location?

Sometimes the location circle thing pops up in my systray indicating that something has requested my location.

In the Windows 10 Privacy Location settings, I can see what can use my location, but is there a way to see what did use my location?

“Your Location Is Currently in Use” is a message that you’re receiving because an app you’ve acquired from the Windows Store is using the Windows 10 system service "Geolocation Service" (named lfsvc) to determine your location. Disabling this service will prevent this behavior but won’t effect other applications (like most web browsers) from roughly figuring out your location through other means.

To enable location services for an individual user and Windows Store app, go to Settings > Privacy > Location > Location service. Slide the toggle to the On or Off position to enable/disable the option for any one Windows Store app.

Windows itself does not provide any direct method for finding out which application is calling the Geolocation Service, so one needs to be a bit creative.

A simple method would be to examine the list of the Windows Store apps enabled to use the Location service, then disable progressively these apps from using it, starting with the most likely candidates, until these notifications stop and do not arrive any more.

The complicated method, suitable for advanced programmers, would be to install and attach the WinDbg debugger to the lfsvc service and set breakpoints on its entry points to trap calls. More information can be found in the Microsoft article How to debug Windows services. Although I have done such debug, albeit using Visual Studio rather than WinDbg, this is not a solution that I would recommend or go into in detail.