What happens if you turn off location access while a hiking app is recording?

The short answer

Losing location access mid-recording does not corrupt the track, crash the app, or throw away anything already logged. It stops the one thing that access controls — new position updates flowing in from the phone's GPS receiver. Everything recorded up to that instant is already written down, and the recording simply goes quiet from there, the same way it would if you walked into a place with no GPS signal at all.

The three ways this actually happens

• iOS periodically shows its own reminder after an app has used background location a number of times, asking whether to keep allowing it, downgrade it to "While Using the App", or stop it entirely — and answering that prompt without reading it closely, mid-walk, is the most common way people cut this off by accident.
• Opening Settings deliberately and changing the app's permission by hand, whether to check what it is set to or to tighten it after seeing that reminder once too often.
• Switching off Location Services entirely, for every app on the phone at once, from the top-level toggle rather than the per-app one — a broader switch, but one with the same practical effect on whatever is currently recording.

All three land in the same place from the recording's point of view: the app stops being handed new coordinates. Which of the three you hit changes how you get updates flowing again, not what happens to the track while they are cut off.

What happens to the recording itself

A recording app worth using writes points to storage continuously, as they arrive, rather than holding a whole hike in memory and saving it once at the end. That is what makes losing access mid-walk survivable rather than costly: everything logged before the cutoff is already sitting in permanent storage, untouched by whatever happens to the permission afterward. There is no separate "save" step for a route to miss out on — the walk was being saved the entire time, and losing access simply means the writes stop happening rather than that something already written gets undone.

What you actually lose is whatever ground gets covered while access is off — a gap in the track for that stretch, not a corrupted or shortened version of the part that came before it. A recording cut off for two minutes while you fumble through a settings screen loses roughly two minutes of position updates, nothing more.

What comes back when you turn it on again

Re-granting "Always" access, or switching Location Services back on, does not rewind anything or try to fill in the gap — it simply lets new positions start flowing again from that point forward, the way GPS reception returning after a stretch with no signal picks up rather than backfills. If the permission was only downgraded to "While Using the App" rather than turned off completely, updates resume as soon as the app is the one on screen, but will stop again the next time the screen locks or you switch away, until "Always" is granted back.

A gap sits in the recorded route the same way a dead phone battery or a force-quit would leave one — distance, time and elevation for the affected stretch are simply not there, rather than being guessed at or stitched together across the missing section.

Things that trip people up

• Assuming the app crashed or the recording was lost outright — nothing crashes; the app is very often still running normally, just not being handed anything new to record.
• Confusing this with Precise Location, a separate setting that controls how exact the coordinates are rather than whether they arrive at all — turning Precise Location off does not stop a recording the way losing location access does.
• Tapping "Keep Only While Using" on the iOS reminder without meaning to, mid-hike, and later finding a gap or an early ending in the route — that reminder exists specifically to catch this choice, and answering it is what downgraded background access from that point on.
• Expecting the missing stretch to be filled in once access is restored — it will not be; a gap during a cutoff behaves like any other stretch that was never recorded, not like a stretch that needs recovering.

Where TrailCam fits in

TrailCam saves a route as it records rather than only at the end, so a stretch recorded with no location access simply leaves a gap rather than costing anything already logged — and if the app is ever interrupted mid-walk, it offers the unfinished route back to you the next time you open it. Recording continues in the background only with "Always" location access granted; downgrading to "While Using the App" has the same effect described above. TrailCam is free to download.