AT&T Galaxy S6 randomly stops sending/receiving SMS after Marshmallow update, other issues

Another commonly reported issue regarding the #GalaxyS6 is about SMS/MMS messaging. This post will tackle a specific SMS issue that started to occur after installing Android Marshmallow. Five more other problems will be equally addressed so we hope that this post will be a good addition as reference for solutions.


Below are the topics we cover in this material:

  1. AT&T Galaxy S6 randomly stops sending/receiving SMS after Marshmallow update
  2. Galaxy S6 Edge Plus won’t power back on
  3. Recover files from water damaged Galaxy S6 Edge Plus
  4. Galaxy S6 Active no longer makes any sound
  5. Galaxy S6 screen is black but phone still rings
  6. Galaxy S6 slow performance issue due to Smart Stay feature

If you are looking for solutions to your own #Android issue, you can contact us by using the link provided at the bottom of this page, or you can install our free app from Google Play Store.

When describing your issue, please be as detailed as possible so we can easily pinpoint a relevant solution. If you can, kindly include the exact error messages you are getting to give us an idea where to start. If you have already tried some troubleshooting steps before emailing us, make sure to mention them so we can skip them in our answers.

Problem #1: AT&T Galaxy S6 randomly stops sending/receiving SMS after Marshmallow update

Since the Marshmallow update, my wife’s Samsung S6 on ATT network will sporadically stop sending or receiving text. When this happens she can not use mobile data either but she can make calls. Had a Samsung tech reset firmware, phone worked fine for a day. If she waits it will start letting her text again or use mobile data. She may fire off 3 or five text then fails to send. Can use mobile data for a while until a text is sent then no more mobile data for a while. It is weird. Where we live both our phones have full bars 4G LTE.

Also sometimes it will say text sent then I might get it 2 hours later or I will send her a text and she will get it an hour later. I have a Note 3 on ATT and I have no issues with my phone. We can tell when the texting and mobile data is going to fail because it starts taking longer and longer for the text messages to say that they sent. And the time they left some times you will get the little spinning circle next to the text message for 3 to 5 minutes and then text fails and mobile data is dead. Sometimes shutting of phone and turning back on helps. Sometimes it doesnt. Sometimes when you turn the phone off and back on it can take a hour to find the tower but that hasn’t happened as much since the firmware reset. That is about all I can’t tell you. I have taken the phone to ATT and to Samsung technician to no avail. Technician said to send it to Samsung. Wanted to try you first to see if you had any thoughts. Tech said it may be antenna but calls work so I don’t see how and have no issues with wifi. — Justin

Solution: Hi Justin. If you’re positive that the issue happens right after Android Marshmallow was installed, then the usual dose of software troubleshooting for this type of issue may help.

Wipe the cache partition. Start with refreshing the system cache. Installation of apps or system updates can sometimes corrupt the old system cache. Deleting it will force the phone to build a new one. This procedure is also very helpful in fixing issues like random reboots, boot loop, stuck during boot up and random freezes after updates. Here’s how you wipe the cache partition on your S6:

  • Turn off the device.
  • Press and hold the following three buttons at the same time: Volume Up key, Home key, and Power key.
  • When the phone vibrates, release the Power key but continue to press and hold the Volume Up key and the Home key.
  • When the Android System Recovery screen appears, release the Volume Up and Home keys.
  • Press the Volume Down key to highlight ‘wipe cache partition.’
  • Press the Power key to select.
  • When the wipe cache partition is complete, ‘Reboot system now’ is highlighted.
  • Press the Power key to restart the device.

Restart the phone in safe mode. One of the reasons why problems occur after a major software overhaul like updating from Lollipop to Marshmallow is because of apps, third party ones especially. To check if that’s the case, you want to try to boot the phone in safe mode as it prevents third party apps and services from running. Then once the phone is already on safe mode, make sure that you observe it for at least 24 hours so you have enough time to replicate the issue. Remember, safe mode won’t help you identify the exact problematic app. If that phone works normally in this mode, you must invest some time and effort to uninstall apps individually and observing the phone after each uninstallation. In other words, you will be doing trial and error method to pinpoint the cause. To boot your phone in safe mode, follow these steps:

  • Press and hold the Volume Down and Power keys for 20 to 30 seconds.
  • Once you see the Samsung logo, release the Power key immediately but continue pressing the Volume Down key.
  • Your phone should continue booting up and you will be prompted to unlock your phone as usual.
  • You will know if the phone successfully booted in safe mode if the text “Safe mode” is displayed at the lower-left corner of the screen.

Update apps and remove incompatible ones. As mentioned above, apps can sometimes cause problems following a system update. Because you update the operating system does not mean apps get their updates too. This is the most often overlooked cause of problems for many users. This can also be the reason sometimes that even a factory reset won’t change anything, especially if users simply re-install the same set of apps. Keep in mind that not all developers are keen on updating their products. That an app works great on Android Lollipop does not necessarily mean it will stay that way once you put Marshmallow on your device. To check if an app is compatible with the OS on your device, visit their main Google Play Store page (assuming you don’t install apps outside of Play Store). The general rule in this case is, if you’re unsure that it’s compatible, uninstall it.

Wipe the phone clean with factory reset. Factory reset should be the last step that you must do on your end to fix this issue of all the steps above won’t work. What it does is restore all software settings back to default, known working state. You are thus effectively eliminating any software glitch that may have developed after the update. After you reset the device, try to observe it again (for 24 hours or longer) just like what you did in safe mode and make sure that you don’t install any apps. If SMS problem is still there, you must find a way to have the phone replaced.

To factory reset your S6, follow these steps:

  • Create a backup of your important files and contacts.
  • Turn off your Samsung Galaxy S6 Edge.
  • Press and hold the Volume Up, Home and Power keys together.
  • When the device powers on and displays ‘Power on logo’, release all keys and the Android icon will appear on the screen.
  • Wait until the Android Recovery Screen appears after about 30 seconds.
  • Using the Volume Down key, highlight the option, ‘wipe data/factory reset’ and press the Power key to select it.
  • Press the Volume Down button again until the option ‘Yes — delete all user data’ is highlighted and then press the Power key to select it.
  • After the reset is complete, highlight ‘Reboot system now’ and hit the Power key to restart the phone.

Problem #2: Galaxy S6 Edge Plus won’t power back on

It started when my Samsung S6 Edge Plus has only 20% battery. I didn’t charge it that night thinking that I might overcharge it because I am about to sleep that time also. The morning after I charged it for an hour or so and when I tried turning it on it won’t. I also noticed that the green light that usually appears when you charge the phone didn’t appear and so is the battery logo. Now I tried charging it with a different charge but still won’t work. So I left it for half a day to charge because I was thinking maybe the battery just got drained, but still it didn’t work. I went to the service center of Samsung and they tried connecting it to a computer and the computer was able to detect it. However they refused to open it because according to them since I bought it in a different country they don’t want to cause any more trouble. I tried resetting it but still won’t work. I only use it for video calls or for internet. It has been with me for only 9 mos. Any suggestions on what should I do? — Aisa

Solution: Hi Aisa. If a computer can still detect the phone, there’s a chance that you may be able to boot it up so you can do something about it. There are three different hardware button combinations that you can try to see which one will boot the phone up.

Boot in Recovery mode:

  • Charge the phone for at least 30 minutes.
  • Press and then hold the Home and Volume UP keys, then press and hold the Power key.
  • When the Samsung Galaxy S7 shows on the screen, release the Power key but continue holding the Home and Volume Up keys.
  • When the Android logo shows, you may release both keys and leave the phone be for about 30 to 60 seconds.
  • Using the Volume Down key, navigate through the options and highlight ‘wipe cache partition.’
  • You can either wipe the cache partition or do a factory reset when in this mode.

Boot in Download Mode:

  • Charge the phone for at least 30 minutes.
  • Press and then hold the Home and Volume DOWN keys, then press and hold the Power key.
  • When the Samsung Galaxy S7 shows on the screen, release the Power key but continue holding the Home and Volume DOWN keys.
  • Wait until the Download screen appears.
  • If you can boot the phone in download mode but not in other modes, that means that your only way out may be to flash a stock or custom firmware.
  • Use Google to look for a guide on how to do it.

Boot in safe mode:

  • Charge the phone for at least 30 minutes.
  • Press and hold the Power button.
  • Once the ‘Samsung Galaxy S7’ logo appears, release the Power key and immediately press and hold the Volume Down button.
  • Continue holding the button until the phone finishes rebooting.
  • Once you see the text “Safe mode” at the bottom left corner of the screen, release the Volume Down button.
  • The only difference of safe mode from normal mode is that the former prevents third party apps from running. If you can boot the phone in safe mode but not in normal mode, uninstall all apps until the issue (that prevents you from booting normally) is eliminated.

Problem #3: Recover files from water damaged Galaxy S6 Edge Plus

Hi The Droid Guy. I was on holiday and went into the ocean forgetting i had my S6 Edge Plus in my pocket. After about 2 minutes, i realized and came out with it and tried to leave it in the sun. I have followed your soft and hard reset instructions to try and get the phone back on again but the phone is lifeless. I tried the rice trick, even blowing hard into the SIM card tray to air out any moisture. The LDI is white and i have checked about 5 times to make sure. Is there another way to try and get the phone switched on as i want to retrieve my pictures, videos and music. Thanks in advance. — Ashley

Solution: Hi Ashley. The only way to access your phone’s memory is by making sure that the phone boots up normally first. If your phone has become totally unresponsive now, those files are good as gone.

Problem #4: Galaxy S6 Active no longer makes any sound

I own and use a Samsung Galaxy S6 Active. Item is not listed but I still need assistance with the phone. I changed a setting and have no idea what I changed but the phone no longer makes any type of sound, doesn’t matter if I am making a call it makes no sound. It doesn’t matter if I accept a call no sound. Yes I have latest update and yes all the sounds are where they need to be. I can’t hear anything from a setting I changed. I appreciate if you can possible assist .

I did not mention In aspects to Samsung galaxy S6 active , it doesn’t makes any type of sound with out without an external speaker (headphone). I changed a setting and have no idea what I changed , the phone does not ring , I can not hear any one speak they can hear me but I have no sound what so ever . Samsung makes NO sound what so ever it can not be a damaged speaker because the headphones plugged into phone does make any sound either. Yes I have latest Firmware update and yes all the sounds on my device are up so I can hear it , just it doesn’t make any type of sound. — Stymeray

Solution: Hi Stymeray. The only effective way to restore the default settings of your phone’s audio system is by doing a factory reset. Kindly refer to the steps above on how to do it.

Problem #5: Galaxy S6 screen is black but phone still rings

Hello there! Well I have a Galaxy S6. I love my phone sooo much! Lately it doesn’t love me. After the successful update from Marshmallow I’ve had a multitude of issues. Sadly it started with the camera. I used to be able to take pictures just fine but now I go to take a picture and it seems like there is an issue with the focus. Then the Camera will actually close. I never know if I actually took the picture unless I go back into the camera and check. Ugh and I find that the response time on opening apps or text messages is ridiculously slow.

Now for the final straw. i was talking on my phone. It had a battery percentage of 89 % which is great for 10:00pm. However I ended my call and set my phone down and now the screen is black. I restarted it. I tried the hold the power button and volume button and nothing works. I took the battery out again and even tried to wait about a half hour. Nothing. What the heck is wrong with my phone? I had my sister call my phone. It rings like normal but there is no screen. I can’t answer the phone now either. I really don’t want to pay $150 for the damn insurance deductible I didn’t do anything wrong. Please help me! — Pollennoel03

Solution: Hi Pollennoel03. well, if the phone still rings when you call it, that’s proof that the problem is isolated to the screen only. Try booting your device to other modes via hardware button combinations (steps provided above). If the screen comes back up to any of the modes, that’s a hint that the cause may be a software glitch.

On the other hand, if the screen becomes unresponsive when you try all the 3 different modes, that suggests that the screen assembly may have simply failed. In this case, there’s no other way but to submit the phone for a repair order so a screen replacement can be performed.

Problem #6: Galaxy S6 slow performance issue due to Smart Stay feature

When processing commands, whether it be turning a page on a Nook reader, or switching between apps, the device won’t respond immediately. The “Smart Stay” eye comes up in the notification window and remains there for a period (sometimes as long as 25 seconds), during which time, nothing external happens. Apparently the commands are stored in a buffer, as they execute once the eye goes out, but the eye will reappear with maddening regularity. Doing a reboot helps, but doesn’t eliminate the problem. — Robert

Solution: Hi Robert. The first step that you want to do is to check if disabling Smart Stay will fix the issue. To do that, simply pull down the status bar, press “Edit,” and toggle off the Smart Stay button. If your phone will work normally when Smart Stay is disabled, then an unknown operating system glitch may be to blame. To fix the problem, make sure that you wipe the cache and data of your Smart Stay app. Here’s how:

  • Open the Settings menu either through your notification shade (drop-down) or through the Settings app in your app drawer.
  • Navigate down to “Apps”. This may be renamed to something like Applications or Application Manager in OEM skinned versions of Android 6.0.
  • Once in there, click on an application.
  • You’ll now see a list of stuff that gives you information about the app, including Storage, Permissions, Memory Use, and more. These are all clickable items. You’ll want to click on Storage.
  • You should now clearly see the Clear Data and Clear Cache buttons for the application.

If wiping the Smart Stay’s cache and data won’t help, make sure to do a factory reset.


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