I've recently reinstalled Pinterest on my iPhone and noticed I was logged in right from the start without even asking me for my username/password, so it must've somehow kept some data on my phone despite the app uninstall/reinstall.

I checked the obvious stuff and it's iCloud Drive as the app doesn't even appear in the iCloud Drive settings so it can't be storing data there. It's not iCloud "look me up by email" either as the app is not listed there either (in fact nothing is listed), and it's not browser cache/cookies as those have been cleared many times after the app was first uninstalled. It's not the iTunes advertising ID either as "limit ad tracking" is enabled and the ID was reset anyway.

Where is this app persisting its data, and how do I prevent this behaviour?


  • 2
    how do you know it's persisting locally? Android apps can see about 3 UIDs with common app perms, i assume iOS is the same way...
    – dandavis
    Oct 15, 2017 at 14:08
  • @dandavis how else would it be persisting? I uninstalled the app, put it back weeks later and it magically brought back my old account - it must've stored its session token somewhere. I'd like to know how to delete this data as I'm concerned it's going to be misused by other apps for tracking. Oct 15, 2017 at 15:01
  • can't they just keep your data on file on their servers, fetching it by unique id when re-installed?
    – dandavis
    Oct 15, 2017 at 15:54
  • @dandavis most likely that's what they are doing - my question is how do I wipe that unique ID? Oct 15, 2017 at 15:56

1 Answer 1


Since iOS 11 it seems like the "keychain" (per-app secure storage for API keys, etc) is no longer deleted once an app is removed, so apps can persist their credentials (and of course ad tracking nonsense) in there and get them back when they're reinstalled.

The only option at the moment is to completely reinstall the device if you want to clear this, as the keychain is per-app so you can't even use another app to clear it, and there is no built-in way to do this. I imagine it would be possible with a jailbreak but that brings its own risks.

I've raised a bug with Apple about this and I suggest you do the same to push them into reverting to the previous behaviour of clearing the keychain of deleted apps.

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