# Data gaps and wrong categorization **URL:** \ **Category:** Arc App Support\ **Created:** [22 March 2024 23:15 UTC](https://support.bigpaua.com/t/data-gaps-and-wrong-categorization/713 "2024-03-22T23:15:30Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![cschick](https://avatars.discourse-cdn.com/v4/letter/c/f0a364/32.png) [@cschick](https://support.bigpaua.com/u/cschick)\ **Post date:** [22 March 2024 23:15 UTC](https://support.bigpaua.com/t/data-gaps-and-wrong-categorization/713/1 "2024-03-22T23:15:30Z")
I’ve a iPhone 15 Pro and latest iOS and Arc. Lately, maybe last month or more, Arc is having a lot of data gaps. Even when it’s the only app open. Also, seems like it can’t differentiate between walking and driving much anymore. Tho when I go to split things, it shows the trace as walking or car as expected. 🤔 In the past, I rarely got data gaps. I’ve just turned on the privacy indicator to see if that helps. Any other suggestions welcome. ---
**Author:** ![matt](https://dub1.discourse-cdn.com/flex013/user_avatar/support.bigpaua.com/matt/32/3_2.png) [@matt](https://support.bigpaua.com/u/matt)\ **Post date:** [23 March 2024 04:46 UTC](https://support.bigpaua.com/t/data-gaps-and-wrong-categorization/713/2 "2024-03-23T04:46:17Z")
Hmm. The other thing I’d recommend, if you’re not doing so already, is running [Arc Mini](https://apps.apple.com/us/app/arc-mini/id1510217238) too. With both running you’re largely protected from data gaps, because one will take over recording if the other is terminated. But from what you describe it sounds like there’s something weirder going on, beyond just normal iOS’s moods and app terminations. > Even when it’s the only app open. By this do you mean other apps have been swiped closed? If so, I’d suggest as a general rule not to do that. It will worsen the phone’s energy efficiency and battery life on average, and possibly teach it bad behaviours in terms of when to keep apps alive in the background. Although I doubt that would be the cause of Arc’s weird behaviour, so that’s just an aside. > [@cschick](#): > > Also, seems like it can’t differentiate between walking and driving much anymore. This also suggests something weirder is going on. Though it’s hard to guess what. It’d be worth having a look at the Classifier Debug View in Arc Mini, to see what the classifier models look like for some common locations. That view will show you the classifiers being used for your current location, so it’d be worth checking it when in one of the areas where it’s been making weird activity type classification decisions. Although given that you’re seeing correct classification when you go into Individual Segments, maybe that’s a red herring, and instead it’s something to do with a backlog of processing timeline data. Which could be happening if the app is getting terminated frequently. It’s probably worth trying to see if you can spot any patterns of where and when it’s getting terminated. If the data gaps are happening in common locations, during common trips, etc. ---
**Author:** ![cschick](https://avatars.discourse-cdn.com/v4/letter/c/f0a364/32.png) [@cschick](https://support.bigpaua.com/u/cschick)\ **Post date:** [24 March 2024 01:46 UTC](https://support.bigpaua.com/t/data-gaps-and-wrong-categorization/713/3 "2024-03-24T01:46:27Z")
Ok, so: 1. install arc mini 2. stop swiping apps closed. (I always thought that was a way to ensure Arc would stay active) 3. start paying attention to any patterns Thanks for the guidance. Let’s give this some time and see what I discover. ---
**Author:** ![matt](https://dub1.discourse-cdn.com/flex013/user_avatar/support.bigpaua.com/matt/32/3_2.png) [@matt](https://support.bigpaua.com/u/matt)\ **Post date:** [24 March 2024 05:53 UTC](https://support.bigpaua.com/t/data-gaps-and-wrong-categorization/713/4 "2024-03-24T05:53:33Z")
> [@cschick](#): > > - stop swiping apps closed. (I always thought that was a way to ensure Arc would stay active) On iOS it’s kind of the opposite of how things work on desktop operating systems. On desktop you ideally want to terminate other apps that you’re not using, because they can continue to use CPU time in the background, and will continue using up memory until terminated. But on iOS when an app goes into the background it’s almost always immediately put into “suspended” state , ie frozen, so that it’s no longer able to do anything, use any CPU time, etc. So background apps don’t typically use any energy or CPU time in the background, unless they have specific permission to continue running in the background (eg background location recording, like Arc). iOS also acts differently from desktop OSes in terms of memory use, in that it will also completely terminate and remove from memory background apps when it wants to use that memory for something else. Desktop OSes don’t typically do that (outside of extreme conditions), so background apps just keep staying there holding onto memory. So yeah, on desktop you kind of want to housekeep apps by explicitly terminating them, but on iOS you’re better off not doing that. Oh, and the reason why not to isn’t just because iOS is doing it itself, but also because an app coming back from suspended state uses much less energy than having to do a fresh launch. Coming back from suspended state costs essentially nothing - the app is just unfrozen and goes back to doing whatever it was doing, at essentially no cost. But a fresh launch after termination means the app has to go through its full startup sequence, loading data, building UI, etc, so it’s costly. That’s why swiping apps closed can often lead to worse battery life over the day. It’s better to have them suspended than terminated. > [@cschick](#): > > 1. start paying attention to any patterns Yeah, I think unfortunately other than installing Arc Mini that’s the best we’ve got. Something weird is going on, but it’s not obvious what yet. So hopefully we can catch it in the act, and pin it down to some specific conditions! ---
**Author:** ![cschick](https://avatars.discourse-cdn.com/v4/letter/c/f0a364/32.png) [@cschick](https://support.bigpaua.com/u/cschick)\ **Post date:** [27 April 2024 16:52 UTC](https://support.bigpaua.com/t/data-gaps-and-wrong-categorization/713/5 "2024-04-27T16:52:30Z")
Go figure. The problem seems to have gone away (I also have Mini running) Thanks. So counterintuitive. ---
**Author:** ![matt](https://dub1.discourse-cdn.com/flex013/user_avatar/support.bigpaua.com/matt/32/3_2.png) [@matt](https://support.bigpaua.com/u/matt)\ **Post date:** [2 May 2024 03:05 UTC](https://support.bigpaua.com/t/data-gaps-and-wrong-categorization/713/6 "2024-05-02T03:05:29Z")
> [@cschick](#): > > So counterintuitive. Yep. Unfortunately that’s my life! These background terminations / data gaps often don’t follow any obvious patterns, and can come and go randomly. There might be months of perfect recording, with no obvious terminations (Arc and Mini might show weeks long uptimes in the debug views), then for no apparent reason there’ll start to be terminations every day. Then it’ll all go back to normal again, even though seemingly nothing has changed 🤷🏻‍♂️ I’m about to ship a new companion app, Arc Timeline Recorder, which is purely for recording, with almost no UI, and with no responsibility for doing daily housekeeping or other background tasks. That means that it always uses under 20-30MB of memory (making it a very unlikely target for terminations due to memory use), and with no chance of spiking or sustained energy use. The new Recorder app should then be able to stay alive almost permanently (almost, because iOS still sometimes terminates all background apps, for Reasons), and give the absolute best chance of avoiding data gaps. I just need to finish up the onboarding for the new app, to get it past App Store review. Hopefully will be live by next week! ---
**Author:** ![Dude](https://avatars.discourse-cdn.com/v4/letter/d/f19dbf/32.png) [@Dude](https://support.bigpaua.com/u/Dude)\ **Post date:** [25 April 2025 03:55 UTC](https://support.bigpaua.com/t/data-gaps-and-wrong-categorization/713/7 "2025-04-25T03:55:03Z")
Hello, I have the same issue as cschick last year. Getting data gaps without the “arc terminated by ios request” message. Downloaded arc mini now as well. Has the issue been found or will it disappear by itself? Have a nice day ---
**Author:** ![matt](https://dub1.discourse-cdn.com/flex013/user_avatar/support.bigpaua.com/matt/32/3_2.png) [@matt](https://support.bigpaua.com/u/matt)\ **Post date:** [25 April 2025 04:14 UTC](https://support.bigpaua.com/t/data-gaps-and-wrong-categorization/713/8 "2025-04-25T04:14:04Z")
Hi @Dude! Instead of Arc Mini, install [Arc Recorder](https://apps.apple.com/app/arc-timeline-recorder/id6499296846). Arc Mini is no longer maintained, and Arc Recorder is the modern replacement for it. > [@Dude](#): > > Has the issue been found or will it disappear by itself? It’s very hard to know what the issue is. There’s various different things that could go wrong, and most of them will be things we can’t debug (they happen when we’re not looking, and don’t produce any logs). But Arc Recorder should hopefully save the day! Let me know how you get on. ---
**Author:** ![cschick](https://avatars.discourse-cdn.com/v4/letter/c/f0a364/32.png) [@cschick](https://support.bigpaua.com/u/cschick)\ **Post date:** [19 June 2025 14:58 UTC](https://support.bigpaua.com/t/data-gaps-and-wrong-categorization/713/9 "2025-06-19T14:58:56Z")
Wow, good run. I’ve been leaving my iOS apps open. I’ve had Arc mini running too. (I must admit I occasionally will tap Arc open to give it a boost - not sure that helps). Alas, don’t know what i did, but today noticed both Arc and Mini were stopped for the past 4+ days (I’ve been busy at a conference, so not doing my usual visits to see my tracking). Oh, well. I can tho attest to the Arc and Mini and leave apps open combination. ![image](https://europe1.discourse-cdn.com/flex013/uploads/bigpaua/original/1X/c756f2ada28fff74cba504f8ffe97ea7c07a99b4.png) ---
**Author:** ![cschick](https://avatars.discourse-cdn.com/v4/letter/c/f0a364/32.png) [@cschick](https://support.bigpaua.com/u/cschick)\ **Post date:** [19 June 2025 18:01 UTC](https://support.bigpaua.com/t/data-gaps-and-wrong-categorization/713/10 "2025-06-19T18:01:24Z")
Oh, now I think I know what happened. My phone died (which a very rare occurrence for me). And the recorders never came back on. Now I know. Haha. ---
**Author:** ![cschick](https://avatars.discourse-cdn.com/v4/letter/c/f0a364/32.png) [@cschick](https://support.bigpaua.com/u/cschick)\ **Post date:** [22 June 2025 19:31 UTC](https://support.bigpaua.com/t/data-gaps-and-wrong-categorization/713/11 "2025-06-22T19:31:22Z")
Hm, last night bot Arc and Arc recorded stopped recording. This time my phone did not die. Nor do I recall getting message Arc was stopped. What’s causing both to completely stop recording. Trying to think what I was doing that might have swamped memory of phone, causing both to stop. Maybe playing with Canva? ---
**Author:** ![matt](https://dub1.discourse-cdn.com/flex013/user_avatar/support.bigpaua.com/matt/32/3_2.png) [@matt](https://support.bigpaua.com/u/matt)\ **Post date:** [25 June 2025 02:25 UTC](https://support.bigpaua.com/t/data-gaps-and-wrong-categorization/713/12 "2025-06-25T02:25:29Z")
@cschick Unfortunately having Mini running might make the situation worse, not better! I’m not sure what the exact cause is, but Mini is deprecated and unmaintained now, so I’m likely never going to find it. Better to just stop using Mini altogether. Run Arc Timeline and Arc Recorder instead. > [@cschick](#): > > I must admit I occasionally will tap Arc open to give it a boost - not sure that helps I’m not certain if it helps either, but I _think_ it does. iOS keeps a record of app foreground time, and likely gives apps more allowances if they’re being actively opened and used at least occasionally. If the app is never opened it’s possibly going to be treated with less respect by iOS. That said, because Arc Recorder has such a low memory and energy profile, iOS tends to leave it alone, running happily in the background for multiple days (or even weeks!) without termination, even if it’s never brought into the foreground. ---
**Author:** ![Dude](https://avatars.discourse-cdn.com/v4/letter/d/f19dbf/32.png) [@Dude](https://support.bigpaua.com/u/Dude)\ **Post date:** [26 June 2025 15:39 UTC](https://support.bigpaua.com/t/data-gaps-and-wrong-categorization/713/13 "2025-06-26T15:39:27Z")
I have a few log files; what do I do with or do I have to upload them somewhere? ---
**Author:** ![matt](https://dub1.discourse-cdn.com/flex013/user_avatar/support.bigpaua.com/matt/32/3_2.png) [@matt](https://support.bigpaua.com/u/matt)\ **Post date:** [27 June 2025 05:53 UTC](https://support.bigpaua.com/t/data-gaps-and-wrong-categorization/713/14 "2025-06-27T05:53:41Z")
@Dude What kind of log files are they? ---
**Author:** ![Dude](https://avatars.discourse-cdn.com/v4/letter/d/f19dbf/32.png) [@Dude](https://support.bigpaua.com/u/Dude)\ **Post date:** [27 June 2025 09:13 UTC](https://support.bigpaua.com/t/data-gaps-and-wrong-categorization/713/15 "2025-06-27T09:13:52Z")
They are from the Arc Recorder. ---
**Author:** ![matt](https://dub1.discourse-cdn.com/flex013/user_avatar/support.bigpaua.com/matt/32/3_2.png) [@matt](https://support.bigpaua.com/u/matt)\ **Post date:** [28 June 2025 05:47 UTC](https://support.bigpaua.com/t/data-gaps-and-wrong-categorization/713/16 "2025-06-28T05:47:44Z")
Ok, cool! In that case, if you’re still getting data gaps, and have log files from Arc Recorder that overlap the time periods of data gap, that could be useful info! Can email them to me at [matt@bigpaua.com](mailto:matt@bigpaua.com). Thanks!