Having had various Android devices over the years I've always thought that this is a ridiculous programming anomoly. You become aware you are starting to run out of space on your device/phone, you try to install something off the Play Store and it just blanks you with "your device has insufficient space" and directs you to look at storage, but then you see you have half a gigabyte remaining and it gives absolutely no indication of how much free space it actually needs, or exactly how much is taken. Seems there is some sort of hidden internal memory where the cache can be filled

Whilst an Android fan in general, I've always hated the insufficient space error and wonder why they haven't been able to come up with anything better by now, such as an easily laid out way of displaying what memory is actually used and exactly how you can free it. Instead it displays only the internal memory space, and not the hidden partition which can be filled by the cache etc or whatever it is, and you get stupid situations like having seeming to have over 500MB still free on the phone and not being to install anything or update anything, this can lead to apps slowly dropping off as some require mandatory updates simply to carry on working!
This is pretty ridiculous programming and you can spend ages freeing up all sorts on your memory and still be plagued by the stupid insufficient space error, now that Android is version 5 or more are they ever going to fix this stupid programming, no matter how big a phone I've got, it always gets plagued by it.

In Windows, you see exactly what hard drive space remains on your windows volume, there's no hidden memory you can see no stats about to plague you when trying to install new programs or files, why should Android be any different?

Presumably because it's used for a kind of swap space, so if you've got a phone with 4GB of RAM like mine it's not really ever used, but on a cheap 500MB RAM model then the internal memory would be used much more by apps and you wouldn't know how much working space they would need necessarily.

It needs that tolerance of not knowing how much swap it'll use I guess, I think it just needs an unclearly defined amount of spare space dependant on a lot of variables, and as a phone OS memory management is kind of meant to be "just let me get on with it, don't worry about that user" as with a lot of under the hood stuff like a true file system you never see as a user (typically), abstract a lot from the user and keep it simple as a phone OS.

The good news is newer phones support huge SD cards, up to 200GB on mine, and if you use cloud services like dropbox you can just have everything work where you take a picture and it's just there in Dropbox for you.

You are running out of space if it warns you, but it as it needs space for it's own use and as a lot of the OS is abstracted from the user it doesn't overcomplicate things. I'd say just go for the bigger storage model, get a bigger SD card, or make more use of the cloud if you're always hitting space issues.

only seen this on really old or very cheap chinese type devices now. They were fine for the level of apps around back then but not for more modern ones. Only one i had any issues with in the last 5 years or so now was one of them hdmi tv plug in things which all seem to come with 8gb memory but about 512 ram and they were always saying insuffucient space.

Not seen it on a phone in years now though.

The main problem I have with it (S4 Mini -- 8GB internal storage, about 5.3GB available after Android CM12.1 is installed), is that Android does not prevent apps from using ever more space for their cache. In order to update Facebook just now, I had to wipe the cache of the Daily Mirror app which had reached about 450MB in size after having it installed for about two months and the size of it was still steadily growing each day. The Mirror app still works fine afterwards, it just needs to download today's stories again.

The Mail is looking a bit on the large size too at around 250MB, and in total across the 110 apps I have installed, the cache now stands at around 1.4GB -- all of which is always on internal storage and cannot be moved safely.

Google should either enforce that apps do more to manage their cache size, or automatically delete old files from it so as to free up space when needed by app installs and updates. Does it really make sense to allow apps to accumulate a total of 2.1GB (as it had reached recently) of junk, on a device with only 5.3GB of internal storage in total? Especially when it then gives a cryptic error message as to why it could not update an app (I knew exactly why it couldn't update, but error 504 or whatever it was will be meaningless to many people).

I hate this on my Sony Xperia Z2! I have 500MB free space on internal storage and apps that are 800KB refuse to download due to lack of storage?

Also Sony found it necessary to alert me with a notification every 5 minutes that I have 75% storage space taken. This is honestly such an annoying thing, I'm fine with having 75% taken. It's got music on it, and photos and apps. If I clear the notification, it'll be back in 5 minutes, and as of lollipop, there's no way to get rid of it for good!

They must know they are not giving users enough information with this, 1: Not revealing how much space is taken by the caches of various apps, 2: Being very unclear about how to free up and where to free up and how much to free up, and 3: Merely telling you to look at your storage cryptically, it must have frustrated a lot of people by now.

I hope to get to a device with 16GB or more internal storage or more at some point because you can actually install more than just a few apps without encountering this for a good while, and I don't really want to fill up the MicroSD card with apps as I have different ones, one with TV & movies, music collections etc, and it's also useful to have enough space to film and take photos for a good while, so internal storage is more ideal for the apps of a phone. I end up having to wipe out the Facebook cache and the Google+ cache etc and then having to re sign in just to get some app on or another, sometimes even that doesn't work and it can be an almighty battle for it to stop cryptically saying there is "insufficient space" despite the over 500MB free on the internal storage, it's ridiculous and certainly needs to be addressed by future versions of Android.`

This! What's the point of having several GB's of internal storage if it is set up in such a way that most people don't realise it is being taken from them in such a ridiculous way, there absolutely should be limits on cache size.

Easy to say, but as apps have so many different functions it isn't always as simple. Maps for example might use a considerable amount of cache as would a browser, other apps might use very little.

I'd say the warning messages could be improved, but ultimately buy enough storage for what you need. If you're fussing about because you've used 80%+ you either didn't buy enough storage, could use cloud storage more or need to delete stuff. Apps do need cache flexibility and Google I assume don't want to put artificial limits in place for what cache apps could use.

Google's Apps seem to stop the free space dropping below 500MB - Google Play Music. Google Play Movies and TV, and (when it was available) You Tube were the same.

Better than some which drop the space to zero though...

In find DiskUsage is a good one for finding which app is munching excessive space.

I largely solved this using App Cache Cleaner ( https://play.google.com/store/apps/d...cache&hl=en_GB) although I assume any other cache cleaning app would work. It seems the OP was right about the cause of this problem.

This happened on every 16GB android device I ever owned. Never saw it happen on the 32GB note 3 or 32GB nexus 7 2013 I owned. I think 16GB jaunt doesn't work on android no matter how you try and manage it.

I chose the nuclear option last night and wiped the entire cache in one go to see how much effect it would have, especially on the apps which were using hundreds of megs of it.

The result: everything works just as they did before, but I now have about 1.7GB of free space on the device. The cache has quickly regrown to around half a gig, but that's reasonable given that I have over a hundred apps on the phone (and yes, I do use most of them regularly).

Twitter, along with certain newspaper apps appear to be the worst offenders for allowing their cache size to grow and grow, at least out of the apps I use.

Wow 100 apps, you maybe should buy the next storage size up next time if you plan to have that many apps installed.

Marshmallow overcomes this by merging SD cards with the internal storage it's just a shame this won't help a lot of people

I was new to Android when I bought it, so I assumed I could just stick everything on an SD card. Of course Marshmallow allows that by swapping the role of the SD card and internal storage, so when a stable build of CM13 is available for it, I'll probably give it a go.

8GB can go a surprisingly long way. I'm not short of space now that the cache has been taken care of. Being rooted helps of course, as any apps with large data or OBB folders can have them moved onto the SD card.