Written by: Ilia
Data recovery specialist, guest author, journalist.
There are many reasons why your phone might suddenly stop recognizing its SIM card. They can depend both on your mobile device and the SIM card itself, and you can fix those problems on your own. Most often, a user might be able to troubleshoot them him/herself.
Physical damage of a SIM card
The most obvious reason why a mobile device can fail at recognizing a SIM card is that it might have damaged contacts, its body might be broken or its shape was changed. In this case a card will be inserted incorrectly in the slot and will be out of order. Therefore, you will have to contact your communications service provider and ask to replace your invalid SIM card.
It's quite possible that your SIM card is simply dirty which influences the ability of your phone to read it. Avoid using water or chemicals for cleaning. We suggest cleaning the contacts with an eraser or a cotton disk damped in alcohol.
Sometimes everything is alright with your card and the problem might with it fitting in the slot. In order to fix this problem, simply put a folded piece of paper between the SIM card and a back cover.
Physical damage of a SIM card slot
This can occur due to the accumulation of dirt, corrosion, physical damage or constant change of SIM cards. In order to figure out whether a slot is damaged, you should first clean it from dirt and dust with alcohol, and then inspect it for any defects or damages of the contacts. There is no way you can fix such damage on your own, so it's better to contact a repair service.
This term is used regarding the devices that are configured for SIM cards from only one specific operator. Such gadgets, especially iPhones are commonly sold on the internet. Be careful or you might accidentally become an owner of such device.
When you buy a device in the store, it's quite easy to notice that your device is "locked". Insert your SIM card in the slot and if there is no connection, this device is automatically configured for one specific operator. The first way to solve such problem is to buy a Turbo-SIM adapter, which is used together with a card and allows you to get rid of the lock. Another way is to adjust the software. We advise you to avoid doing it on your own otherwise you can damage the device. In order to be on the safe side, go to the service center. And it's even better to check the device before purchasing it and after finding out that it's "locked" you can refuse to purchase it.
If a SIM card not readable, keep in mind the possibility of software failures, in particular, incorrect settings of your phone/tablet.
How to fix a sim card that wont read:
If flight mode or standalone (do not disturb) mode is enabled, communication services aren't provided. Check whether one of these modes is activated on your phone.
Turn off your device, remove the SIM card and after a while insert it again. Restart your gadget.
Check whether your SIM card is activated. If not, dial the special activation number (each operator provides it during the purchase of a card).
See whether your SIM can be registered in the network. In order to do this, go to the Settings, find "Mobile networks" tab (Sim card status). The device will find all the possible connections, from which you should select the one you want.
If none of the mentioned above methods work out, perform a hard reset (Settings - General management - Reset - Factory data reset). This will result in the loss of all data and apps stored on your device. Therefore, we suggest using it only as a last resort when none of the other troubleshooting variants led to the desired result. First of all, you should create a backup copy.
A phone with two SIM cards
Currently, dual SIM models are very popular (for example, in Samsung Galaxy phones, LG, etc.). This allows you to enjoy the services provided by different mobile operators. But sometimes using two SIM cards might be quite puzzling. This happens if users forget to enable one of the two cards in the settings of their device. Such problem can easily be fixed.
- Go to the Settings;
- Open "SIM card manager";
- Switch to the desired SIM card.
You can set the conditions for a SIM card, for example, when making calls, sending SMS messages or using the internet. This can be done via "SIM card management" in the settings menu.
When one of the two SIM cards isn't displayed (or you see the message "No sim card inserted"), you have to check it by installing it in another slot. If everything works fine, it might mean that the problem is in a gadget itself. This may happen as a result of incorrect reflashing or IMEI error. In case of the 1st option, download software from an official website or "reset" your device. And in case of the 2nd option, find out whether IMEI on the body of a device and in the program are the same. You can check it by typing *#06#.
Damaged NVRAM problem
NVRAM is a part of memory on Android which records information on IMEI-code, SIM cards and etc. Due to incorrect reflashing this file may be damaged or deleted. As a result, the operation of a device is disrupted, including its ability to recognize a SIM card. There are two ways to find out if NVRAM is lost:
- Connect to Wi-Fi and find the network "NVRAM warning err=0x10".
- Dial *#06# and as a result you won't receive a message with IMEI.
You can restore this part of memory from a backup or via special utilities. In order to be able to work with a backup copy you have to, first of all, create it, and, secondly, gain root access (superSU). The sequence of actions:
- Open a recovery app (see below);
- Connect your device to a computer;
- Activate root access;
- Select "Restore" and follow the system instructions.
There is a great variety of NVRAM recovery utilities which are available for free download on the internet. Such as TWRP Recovery, SP Flash Tool, MTK Android Tools or ADB. The manuals on how to use them can be found on their websites.
Invalid code or incorrect network settings on Android phone
If you enter the wrong PIN several times, your SIM card will be blocked. You can regain access via PUK code. However, if it has also been lost or entered incorrectly ten times, you won't be able to unlock the card on your own. You will have to contact the operator and provide the passport details of the owner.
Sometimes the network settings can be set incorrectly, as a result of it a SIM card can't find the network or register in it. This may be a result of a SIM card change or the reconfiguration of networks. In order to fix the settings, you have to contact your mobile operator.
Any problems that arise while you use a SIM card can be eliminated by calling the contact center or by contacting the service department.