Unrooted Samsung Galaxy S5 running Lollipop 5.0 randomly reboots

Question

Since I installed Lollipop on my Galaxy S5, my phone is trying to reboot itself randomly approximately once a week. But it gets stuck on the boot-up logo screen then, only showing the word SAMSUNG there.

If I don't do anything about it, the display is lit up with the logo, until the battery is completely emptied (the battery-graph will show a gap for that time later, not telling me what could have happened). This is especially very annoying at night, since I use my phone as an alarm-clock ;)

Does anyone have suggestions about it? Anything to disable that may cause these spontaneous reboot-attempts?

• The phone is not branded
• I did not root it
• I already tried to 'factory-reset' my device
• Everything worked fine prior the Lollipop-Upgrade

Answer 1

After several weeks of trial and error, I might have found a workaround or possible solution:

If you can get on without certain compulsory-apps, that came to your phone with Samsung's Edition of Android, you should consider disabling the following services in Android application manager:

• S Health
• S Voice
• Samsung Account
• Samsung Galaxy
• Samsung Link Platform
• Samsung Link Platform Connectivity
• Samsung Push Service
• Unified Daemon

Note, that if you disable 'Unified Daemon' and 'Samsung Push Service', 'Samsung-Account' and other Samsung-features also won't work properly any more. Keep in mind, that 'Geo News' also depends on the 'Unified Daemon'! Samsung's backup-/restore-features are negatively affected, if you disable one of the 'Link Platform'-services, but Android's features still work as expected!

The list above contains apps/services, that (for me) are highly suspicious of causing the described problem, but for the sake of completeness, here's the complete list of apps/services, I have disabled (not uninstalled - since this would require root-access):

• ANT Radio Service
• ANT+ Plugins Service
• b2b.hrs.android.lib
• BlurbCheckout
• ChatON
• de.pizza.lib
• Group Play
• S Beam
• S Health
• S Planner
• S Voice
• Samsung Account
• Samsung Apps
• Samsung Billing
• Samsung Galaxy (I don't actually know, what this one does, but the phone does not need it to work properly)
• Samsung GALAXY Apps Widget
• Samsung Link Platform
• Samsung Link Platform Connectivity
• Samsung Print Service Plugin
• Samsung Push Service
• Smart Remote
• TalkBack
• Unified Daemon

In the last 3 weeks, the problem never occurred again - and I'm not missing any of the features above. As a positive side-effect, there are no more lags or hangs on my phone any more...