Many people have had problems updating their iOS device to iOS 8 because they don’t have enough space. The weird thing is that many of us have plenty of space, except there’s a mysterious padding of yellow marked “Other” that is, well, unknown.

This has been going on for quite a while, and after some prodding from Wave and Gruber, I figured it was time to do some research. So, in pictures, here’s what I found. I started out by attaching my iPad mini to my Macbook and resetting it to basic settings. This wiped everything out of it, and updated the software to 8.1, which was dandy. It also meant that I had nothing much at all on the machine. Here’s what you see (and I did full screenshots so you can see the date and times of this, as the experiment lasted overnight).

That bar along the bottom is the thing. I had the apps that come installed with the OS and nothing else on this, except for a few photos and such. Here’s what my iPad showed for usage, both summary and itemized:

Everything seems fine. Now, to figure out what is filling the space, I did what I like to do when my TV is busy doing other things, and I want to watch a movie, maybe a TV show, from iTunes – I stream it to my iPad. So for this, I chose X-Men: Days of Future Past, and watched that, which took a couple hours. Here’s what I get after:

In the first screen shot, I’ve gone from having 10.0 GB available to having only 5.5 GB available. And if we look at the size of the movie file from iTunes, guess how big it is. Yep, 4.5 GB. But notice that the second screenshot, which was taken at the same time, doesn’t show any change. In fact, Movies aren’t listed at all, still, even tho I watched one.

So I decided to watch another. Time for “V for Vendetta” because who doesn’t love that? I know, everyone loves it. So after a few hours, I thoroughly remember the 5th of November, but I still wonder about that mysterious other. So again, into the usage and here’s what I found:

Now I’m down to a gig and nothing has changed on my itemized list. Well damn. Let’s watch Captain America: The Winter Soldier next because I enjoy the film and it’s getting late. So I fired that up.

Right about the time I get to the scene where Cap is taking on the terrorist on the boat, I get this notification:

We all knew this was coming. Cap definitely weighs in at more than a gig, and that’s all the free space we had. But this is just a warning. The video still plays a bit more.

“You have three.”

The video is done. Nothing more will play. At this point in the movie, which if I hadn’t seen it before I would have been livid that it stopped there, the action is just heating up, but I can’t play it. It’s failing. Stuttering and then just playing a bit of audio, then stopping completely.

So here’s where it gets interesting. I checked the usage again:

Now down to a measly 208 MB, but the itemized usage hasn’t changed. Not good.

I go back to the video and try to watch it again. I get a few minutes farther, to this point:

“Wanna see my lease?”

No, but I’d really like to know why video is becoming “other” and why I can’t delete it. That’s the only explanation. And with only 207 MB left, the iPad is not working well. But I decide to try to install a couple apps to see if I can get anything working. So I look for Facebook, and I can’t find it, but I install Facebook Messenger:

And here’s the screenshots of my two springboard pages:

Again, not much there. But let’s see if we can install anything.

Huh, it seems it’s going to install. That’s cool. But what the hell, where’s the actual Facebook App? I go into Settings to see:

I have no idea, and solving that problem is beyond the scope of this article, but something is weird there. Anyway, it’s not the only weird thing. Now that I’ve installed an app, check out the Usage stats:

Wait, what? I have free space again? I install a random app, and finally the OS deletes some mysterious other to be able to install stuff? This is new. So I decide to watch Captain America again, because I want to know if I’ll get all the way through it – and I did!

But wait, what’s the usage at now?

And other than the new app being in place, the itemized screen really hasn’t changed. So I came to my desk and got another screenshot:

Now, full disclosure, I knew this was the problem with what creates the mysterious other in the OS, and is causing so many issues. Now, I used to have a developer account I could access to see the names of the files that made up any particular category, and that’s how I knew what was causing this issue. The only new thing was that installing an app apparently deleted some of the other, but not all of it. And it’s very simple to fill it back up. It’s a bug, and easily reproducible, so I’m hoping that Apple fix it.