As I’ve been using my iPhone more for storing and playing back music to listen to in the 2014 Honda CR-V, I’ve been much more attentive to how much space data is taking up on the phone. My 16GB iPhone 4s has been precariously close to its limit, with the storage summary in iTunes showing that about five gigabytes were consumed by “Documents and Data” and “Other”.
Looking at neither iTunes nor the iPhone interface revealed any clues as to what these categories of data represented. I know that I store applications and audio on the phone, both of which were already accounted for with about three gigabytes each. I had already deleted a bunch of pictures to clear up space. But where was all of this other data and other “other” coming from?
Poking around on the web suggested trying out iMazing, a desktop application for exploring the raw iOS file system. Sometimes, supposedly, voice memos can get repeatedly duplicated, taking up a lot of space, or maybe some other temporary cache files can get out of hand. I didn’t see any obvious waste of stored data on the file system, but I tentatively tried deleting a few files that appeared to be unneeded cache, and synced my phone with iTunes to see if it made any difference at all.
Nearly all of both the “Documents and Data” and “Other” data disappeared, leaving five gigabytes of usable space in their stead.
I have absolutely no idea how the few small cache files that I deleted could have had this large of an impact. The phone seems to still be working as expected. I guess I’m pleased with the results, even though I do not understand how they came to be…
[Update: after several more days of using the iPhone, it became apparent that all was not quite well. When trying to play many songs from the music player, the songs would disappear from view. Sometimes entire albums disappeared. I fixed this by removing all music from the iPhone, and then putting it back on. Along with the repaired music came 3 gigabytes of "Other" data again! I still have 3 gigabytes free, but am puzzled as to why 4 gigabytes of audio files need to be accompanied by 3 gigabytes of "Other" in order to be played back from the iPhone?]
[Update 2: Further web searching suggests the classic method of backing up your iPhone to your computer, erasing the data from the iPhone, and restoring from the computer backup. This resulted in a significant reduction of "Other" data, giving me nearly 6 gigabytes of free space again.]