SD card usage after updating to Windows Phone 8.1 dev preview

I have a small SD card (1.83 GB) inserted in my Lumia 525 that I'm using to store some music and images.

Before I updated my phone to Windows Phone 8.1 dev preview, I had roughly 100 MB of free space. Upon updating, it had suddenly gone down to 0 KB. Yet when I added up the data in the memory stick, it was only close to 1.7 GB, and thus should've had ~100 MB free.

I couldn't figure out what was happening, so I decided to format the memory stick. After formatting, I clearly had all of 1.83 GB free. Then I copied around 800 MB of music and around 600 MB of images. But after that, instead of having the expected ~400 MB of free space, I have just 12 MB. Just like before, the space had vanished magically. (Note that I did nothing other than just copy the files, though I did notice that copying the images took a long time unlike before.)

Even now, if I check the size of all the folders in the SD card, they add up to only 1.35 GB.


Yet, only 12 MB is free.


What is happening here? And no, I haven't installed any apps onto the SD card, and new apps are set to be installed into the phone's internal memory.

I was planning on buying a large SD card now that apps can be installed onto it, but if the space is just going to be eaten up, I'm not so sure.

GoodDayToDie said:

Do you have "Show Hidden and System files" enabled in Folder Options?

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Yeah, I do. "Show hidden files and folders" option is selected, and "Hide protected operating system files" option is unchecked. These are all there is in the SD card.

And now not just the SD card, but it also happens in the phone memory. Had 1.9 GB free. Copied 600 MB of images. Suddenly only 900 MB free. Might have to reset the phone to get that space back now. This is a real annoyance.

GoodDayToDie said:

Do you have "Show Hidden and System files" enabled in Folder Options?

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Click to collapse

kiss.adam.pacman said:

Mtp could hide a hold file system. Some of the elic hidden folders can be watched with mediaajdio2 plugin, but the best ghing you can do for investigate is to pu off the card and check the fs with a card reader. But there might be some morereally fs hodden folder, but 99% therd wont be

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Thanks for the idea of using a card reader. That helped me get to the root of the mystery, though I don't know how to fix it yet.

Alright, so I formatted the SD card again, copied my music into it again, and checked the free space. No problems.

Next, I copied ~100 MB of images. Again, ~160 MB space was lost instead of ~100 MB.

And then, I put the SD card into the card reader. Here, it showed a hidden folder WPSystem. Inside, as shown below, it's as if it's keeping a slightly downscaled copy of every single image I copy into it.



This is where the space is going. And this is extremely irritating. I read comics and manga a lot on this phone, and they're most of the time in the format of seperate images, totalling upto several hundereds of MB. When each 100 MB means I lose like an additional 60 MB, it becomes a huge waste of space.

Does anyone know why this might be happening and what I could do to stop this? This wasn't happening until I updated to 8.1. If someone here has some time to kill, I'd be glad if they could copy a few hundred MB of images to their phone and see whether this occurs. Copying this much of image files into their phones is not something most people do, so this bug might be overlooked.