When your Android phone or tablet is working just fine and doing what you want, it's easy to forget it's a computer.
But every so often, something goes wrong, something does not work. And the guts of your phone—its UNIX-based file system, its weird partitions, its odd dependencies. The little persnickety man pulling the gears for the seemingly humanoid robot appears, and he is unhappy.
Such is the case when you, the owner of a phone that purports to have something like 16 GB or 32 GB in storage, cannot install an app, even a small one. Your phone has a few apps on it, maybe a bit of music and some photos, but you are, you believe, nowhere near your size limit. But the next time you install, or try to update, you get a message: "Insufficient storage available."
I just received this while trying to update Yelp, of all things. I went into the Storage area of Settings, and found that I have 10.32 GB of space available out of a total 25.59 GB. So that should be enough to simply update Yelp, which is a bit more than 11 MB if you install it new, and the updates are usually just changes with much smaller file sizes. But it's not, because "Insufficient storage available," every time.
The thing about "Insufficient storage available" is that, like its UNIX-like lever-puller, it's not great at telling you exactly what's wrong, just what it can report about that thing you tried to do. I have seen people complain about storage issues on big phones before, like the Galaxy S4, which makes less than half of its 16 GB version available to owners. I remembered making Midas-like decisions about which apps to keep on my Nexus One. I had thought that, with newer phones with much more storage, that app limitations were a thing of the past.
No so, it seems: "Insufficient Storage Available" still comes up, but for different reasons. I wanted to put together here all the reasons an Android phone might see this error. Let's get into it.
First: let us distinguish between "internal" and "external" storage
On phones where the memory is physically built into the device and is not a physical micro SD card that can be swapped out, the storage is all usually one big block: photos, music, applications, the system itself, and everything else uses up space, and you hopefully have enough.
On phones with removable storage, and some older phones and versions of Android, there are separate sections of memory: "System," for your core phone functions and the apps you install, and "USB" or "SD" or "External" storage, where all the stuff you create will go. Why the division? The key reason is security: apps installed to "Internal storage" have pieces that cannot be modified by the user or other apps. That's key for apps that have tricky internals, but even more necessary for apps that require a paid license, offer in-app purchases, or authenticate you with an online account.
"External storage," however, is just a chunk of space available to the phone owner and app makers. You can access it from your phone or a computer to which you connect your phone by a USB cable. The reason most apps choose not to install there by default is that when you do plug your device in and access its storage (with a computer, in a car, or anywhere else), those apps are no longer accessible, because the storage has been "mounted" elsewhere. Like I said: UNIX, man.
Again: not every Android device has these distinctions. And some apps split their core functions and data across internal and external storage. But you may still run out of space to install apps, regardless of how your space is divided up. Some of the tips and tools that follow will help with that matter, too.