Factory resets on mobile phones... do they really clear all your data?

[Nix]

So, do they? I see people selling their old phones all the time... I presume they all do factory resets but is that enough to delete your data so none else can get it if you sell your phone?

 

[Floris]

One thing you can do yourself before you factory reset it, is to make sure you are no longer logged in on that phone to iCloud and other services. Maybe set a different pin for just that phone. And forget the wifi it connects to, and then turn wifi off, and purge some of the data on there. From documents downloads, to images, videos, etc. Then factory reset when you're ready.

 

[ChattingWithYou]

Oh! And I thought that factory reset would delete all my data......
There are so many options available on the internet to protect our data from falling into wrong hands. It is better to encrypt our data and overwrite it with junk data and then factory reset after removing the SIM and memory card.

 

[SaadAkbar]

Your data can be recovered even after factory data reset.The only option is to completey wipe software from mobile and install new software.Your data can't be retrieved then.

 

[Floris]

And I thought that factory reset would delete all my data

Unfortunately, with the right forensic tools it is possible to view some of the data that's on a device that's unencrypted and in plain text (documents, images, etc) Apple makes it pretty tough to get to it, but it's not impossible. Special but affordable devices know what to do and what to look for.

You made a good point, some people leave the sim card in the phone they sell, they totally forget to remove it.

The only option is to completey wipe software from mobile and install new software.

Indeed, multiple wipes will write data over the same areas on the storage, making it a lot harder to properly restore the original data there. But I think that a lot of people don't know how to do this.