How to fix This SIM Card is from an unknown source error on the Samsung Galaxy S5. The US variants of Android phones are locked to a specific carrier and use a mobile contract that is offered by that carrier. Each plan lasts for around 2 years. So for 2 years you are stuck with the same phone on the same contract carrier.
This is a good thing because you benefit from the best offers and low prices that the carrier has. On the other hand, you might not be happy with your current phone company for many reasons. Prices might get expensive, internet speed might become slow and the overall signal can be very poor.
As you can see, there are many reasons why you want to switch from your current phone carrier to another one. One of the first things you should do once you have decided to switch is to SIM unlock your phone. The phone is locked to that specific company and if you use another SIM card it will not work unless you SIM unlock it. Check our guide here to SIM unlock the Samsung Galaxy S5 to all carriers.
Once you have unlocked your phone, you can insert every SIM card you want. Now, another problem has showed app. On a few Galaxy S5 units, every time a new SIM card is inserted, “This SIM Card is from an unknown source” error shows up.
Basically, this error notifies the user that the card is not designed to work with the current phone. This error is caused by the old carrier applications. Carriers always put a lot of third-party applications to Android phones. These apps are carrier related and have multiple functions.
One of these functions is to check what kind of SIM card the phone has. When the app notices that the SIM card is not from its carrier, it displays “This SIM Card is from an unknown source” error which cannot be removed. Follow the guide below to fix and disable “This SIM Card is from an unknown source” error.
Step 1. In order to remove all the applications, not only disable them, you should be rooted. Follow the guide here to root your Galaxy S5.
Step 2. Using a good file explorer, go to System > Apps. There will be listed all installed applications.
Step 3. Search and find all the applications which have the carrier name. For example, a Verizon phone has the following application name: vzwphoneservice.apk.
Step 4. Once you have found the files, rename the first part and replace it with your carrier name.
Step 5. Click save and reboot your phone.
Also, download root uninstaller from the store and uninstall all carrier apps that you can find on the app drawer of your Samsung Galaxy S5.