How to fix Samsung Galaxy S6 that keeps restarting after Android 6.0.1 Marshmallow update

It seems that there are so many Samsung Galaxy S6 (#Samsung #GalaxyS6) owners that are experiencing the random reboot issue after updating their device to the latest Marshmallow firmware. If the phone randomly restarts on its own, it’s an indication that the firmware or the operating system is corrupt or there are some files missing and since we don’t know which is which, we need to do some troubleshooting procedures that may help us fix it.

Here is one of the problems we received from our readers that best describes the issue:

Hi guys. I need your help fix the issue with my phone. It’s a Galaxy S6 which I bought brand new. There was a notification about an update so I downloaded it. It was successful and I was able to use my phone for several hours before the first instance of the problem occurred–it rebooted on its own.

At first, I thought it was just some kind of a glitch so I didn’t mind it. The day after the first incident, the problem occurred again, then after a few hours it rebooted again and now it’s getting more frequent than before. There was even a time that I was in the middle of a call when it happened, so the call was dropped. I don’t want that to happen because people might think I’m dropping their calls. So, what do I need to do? Thanks.

The problem above is showing just one of the signs of the problem. There are actually other signs you may encounter that may lead to the same result–unwanted reboots. So, let me list down the possible symptoms of this problem:

  • Just like the problem cited above, the reboots may become more frequent until such time you can no longer use the phone because it restarts every few minutes
  • There were also reports that the phone freezes for a long time and becomes unresponsive and then it reboots only to do the same thing when it’s back up
  • Some reported that their devices restarted after using certain apps which indicates that the problem can also be app-related

Now that you know the other signs of the problem, it’s time we look into the possible causes based on reports and testimonies of the owners:

  • Some apps may crash due to incompatibility issue with the new firmware causing the system to crash as well
  • The new system still uses the caches of the previous firmware and caused inconsistencies during the operation
  • The firmware itself is corrupted and needs to be reinstalled
  • Some files are missing due to bad or interrupted update
  • The device suffered liquid or physical damage that caused inconsistencies with the hardware

Before we jump into your troubleshooting procedures, if you have other issues with your phone, visit our Galaxy S6 troubleshooting page and find issues that are similar to yours. You may then use the solutions we provided or if you need further assistance, contact us by completing our questionnaire.

Step-by-step Troubleshooting

The purpose of our troubleshooting is to know what the problem is. Yes we know that the issue started after the Marshmallow update but we really don’t have any idea what triggered it. So, let’s try to rule out one possibility after another and let’s begin with apps.

Step 1: Incompatible apps are conflicting with the new firmware 

If an app is incompatible with the new system, it crashes when you open it. But some actually do more damage and this problem is just one of them. So, to rule out this possibility, we recommend you boot your Galaxy S6 in safe mode to temporarily disable all third-party apps. This way, we can isolate immediately if the apps that cause the problem are pre-installed or downloaded:

  1. Turn off your Galaxy S6.
  2. Press and hold the Power key.
  3. When ‘Samsung Galaxy S6’ appears, immediately release the Power key and then press and hold the Volume Down button.
  4. Continue holding the Volume Down button until the phone finishes the restart.
  5. When you see Safe Mode on the lower left corner of the screen, release the button.

If the problem doesn’t occur in safe mode, then it’s obvious one or some of your downloaded apps is causing the problem. You need to look for those apps and update or uninstall them.

Try booting back in normal mode and open your frequently used apps. Try opening one after another until the phone reboots. The one you’re using when the phone restarted might be one of the culprits. Try disabling it first or just go ahead and uninstall it.

Should the phone reboot randomly even in safe mode, then proceed to the next step.

Step 2: Some caches may have been corrupted during the update process

System caches are important to make the phone run smoothly. However, some of the caches may get corrupted during major update like the one you just have, i.e. from KitKat to Marshmallow. Even though these files are corrupt, the new system may still continue using them. Consequently, inconsistencies occur leaving the device freezing, unresponsive or to randomly reboot.

You need to delete the cache so that the new system will create new files that are compatible with it and since it’s not just files like any other, you don’t have access to them. You cannot delete cache files one by one. So, what you need is to boot your device in recovery mode and delete the contents of the cache partition. Here’s the step-by-step instruction…

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

Wiping the cache partition is almost the same as the factory reset only that you are not deleting data but system caches. It’s a very effective troubleshooting procedure you should use before deciding to do a reset. And the good thing about it is that none of your files, apps, contacts, etc. will be deleted. However, if it failed to fix the problem, then you have to do the reset.

Step 3: Some system and apps data may have been corrupted during the update process

For average users, this is as far as  you can go and if the issue persists after doing the procedure below, then it’s time  to seek help from a technician.

This is the same as the factory reset only that it is done in recovery mode and that the data and cache partitions will reformatted when you do it.

The downside of this procedure, however, is that if you forgot your Google account’s username and password and you haven’t removed your account from your phone before the reset or if the screen lock was still engaged, the Factory Reset Protection or FRP will be tripped and you will have a hard time logging back into your phone.

So, before the reset, make sure you remove your Google account and the screen lock disengaged.

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

Step 4: It’s time you sent the phone in for checkup and/or firmware reinstallation

Apparently it is a firmware issue but since manually installing a firmware will void the warranty, you cannot just do it by yourself. You need an authorized technician to do it for you so you either bring the phone to your provider or have Samsung take care of it for you. The compromise is you’ll have to wait for a few weeks before you get your phone back.

But just to give you an overview, for firmware-related issue just like this, the new firmware will just be reinstalled to make sure its integrity is intact. If the problem is the new firmware, then any technician can roll back to the previous firmware.

If, however, you are savvy enough and don’t care about the warranty, then you can do it yourself. All you need is the firmware downloaded to your computer and the Odin flashing tool. Once you have these things, use your computer to install it to your phone.

I hope that this guide helped shed some light to your problem or question. If you need further assistance, feel free to leave a comment or contact us.

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Harold Hisona

Harold has been in the tech industry since 2008 when he started out as a tech support for companies like Time Warner, Comcast and Tracfone. He’s been troubleshooting phones when the smartphone industry started booming. During his tenure as a tech support, he’s already been writing for various tech blogs and doing some freelance SEO. In 2012, he joined a small team of bloggers to write for The Droid Guy, and he has been with the company ever since. Today, he doesn’t only write tutorials and troubleshooting pieces but also shoots and edits videos for The Droid Guy channel while trading stocks on the side. Contact me at Email

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