Not enough storage to backup iPhone after iOS 13.5.1

I'd almost forgotten there were iPhones still supported with only 16GB of memory... I can see how this would crush your productivity.

I ended up solving it myself today after reaching my wit's end. Seems like the progression for most folks to get this fixed is:

1. If 13.5.1 was recently installed, give it 24-36 hours to "Index" and perhaps go back to normal.
2. If #1 doesn't work, try to restart the device.
3. If #2 doesn't work, connect to a PC/Mac with iTunes or Catalina and Sync the Device
4. If #3 doesn't work, attempt a local backup. (Some report this is enough to get the system to re-index its memory files and caches) If that doesn't work, you'll likely need to go to Option #5, so do the best you can to back it up to iCloud if the local option is blocked by an erroneous lack of storage message.
5. If #4 doesn't work (my situation), Erase All Content and Settings, and upon re-initialization Restore Manually from a Backup (or iCloud if you must)

There's undoubtedly a more technical and permanent fix to this, but I'm neither a developer / programmer and the entire iOS is essentially locked down anyway so not much you could do to fix the OS.

SravanKrA,

Thanks for taking the time to respond. I'm aware of what the "Other" category is supposed to contain and how it's supposed to be managed. Unfortunately, the system is NOT properly managing these files.

Case in point: I deleted over 1.5 GBs of content in the last week. Within a day, the "Other" category ballooned with minimal device usage to fill the drive within 200MB of completely full. I've deleted Safari Cache and browsing data, and anything else I can access, turned off Siri, etc... to no avail. At one point last evening I deleted 400MBs of downloaded podcast material. The Storage updated to show the space... and then BOOM! instant return of "Other Files" back to that threshold. It seems to vary only by approximately .1-.3GB at most.

Other users are reporting this issue saying that a Sync/Backup to a computer works - but now the phone won't backup because it erroneously states my computer doesn't have enough space to conduct the backup. I have over a half Terabyte available... that's plenty.

Something is definitely wrong with memory handling. My only recourse will likely be a full reset, which will be a pain to manage with my 2FA tokens.

I gave up waiting on hope for an easy fix since it's unlikely that Apple would either acknowledge the issue or have a fix for the issue outside of a software update and decided to go with the "nuclear" option.

Only after a complete Erase and Reinstall from an older backup was I able to get things back up and running. Luckily I salvaged most (not all) of my App Data. Unfortunately the problem kept me from completing more recent local backups and I'd deleted some (unimportant) material prior to resorting to the Wipe/Reinstall.

Note: If you're like me and use 2FA tokens, you'll need to port them to an App like Microsoft's Authenticator which backs tokens up to iCloud. I luckily remembered Google's Authenticator tool can't be remote backed up or recovered after a phone wipe, so depending on your security settings and access to backup codes you might be "up the creek" if you have to do this on short notice.

With almost all of my original data back on the phone I went from about 17GB of "other" to just over 2GB. The reset also now allows my iPhone to complete the encrypted backup process to a local computer.

I'll be curious to see if this is addressed in a future iOS update.