"Locked" gets used for at least three different things, and mixing them up is the single most common mistake people make when buying or troubleshooting a used phone.
The three locks
| Lock type | What it restricts | Who can remove it |
|---|---|---|
| Carrier / network lock | Which SIM cards the phone will accept | The carrier, or an unlock service like this one |
| iCloud Activation Lock (Apple) | Using the device at all until the owner's Apple ID signs out | Only the original account owner, from their Apple ID |
| FRP — Factory Reset Protection (Android/Google) | Using the device after a factory reset until the previous Google account signs in | Only the original account owner, from their Google account |
| Reactivation lock (Samsung) | Android's FRP idea, implemented at the Samsung account level via Find My Mobile | Only the original account owner, from their Samsung account |
Notice the pattern in that last column: for two of the three lock types, only the original owner can remove it, from their own account. We are never that owner, which is precisely why this is the one category of lock we're upfront about not being able to help with.
Why these locks exist in the first place
Each one solves a different problem. A carrier lock protects a network's investment in a subsidized or financed device. iCloud Activation Lock and FRP protect the phone's owner: if a phone is lost or stolen, whoever ends up with it can't simply factory-reset it and start using it as their own — the phone stays tied to the original account until that owner explicitly releases it. That's a deliberate anti-theft design, not a bug or an oversight.
Why they get confused
All three can make a phone unusable in some way, and all three get called "locked" in casual conversation. But they're independent systems, run by different companies for different reasons: a phone can be fully carrier-unlocked and still Activation Locked, and a phone can be Activation-Lock-free while still restricted to one carrier. Fixing one never fixes the other, and no legitimate service can bundle all three into a single step.
How to check before you buy or before you troubleshoot
- iPhone: ask the seller to open Settings and confirm Find My iPhone is off, or to sign out of their Apple ID in front of you.
- Android: ask the seller to remove their Google account from the phone (Settings → Accounts) before you finalize the purchase.
- If the seller can't or won't do either, treat that as a hard stop rather than something to resolve after the sale.
- Either way, a phone that still shows someone else's account is a phone you should not pay for.
For the carrier-lock side of things, carrier-locked vs. unlocked phones covers what that restriction actually does, and checking a used phone's IMEI before you buy covers the full pre-purchase routine.
