[Magisk] TheCech12:
I don't want to use this workaround, because it is not made for Samsung devices. But I tried to use it, to fix the problem with Magisk Hide. I hope we can focus now the problem with Magisk Hide.

Hey Didgeridoohan,

thank you for your quick answer! I hope, we will find a solution and it will help some other persons, too. :)

Unfortunatly Magisk Hide does not work.

Now I wiped the whole device and I flashed LineageOS 14.1, Open Gapps (pico) and Magisk. I install Magisk Manager, install Root Checker, enable Magisk Hide, add Root Checker to hide list, restart phone.

I start Root Checker and it asked anyhow for root privileges and if I choose "yes" it has root privileges, if I choose "no" it has no root but it detects su.

I install Android Terminal Emulator: Here is the output of disabling and enabling Magisk Hide via terminal:

i9300:/ $ su
i9300:/ # cd /magisk/.core/magiskhide/
i9300:/magisk/.core/magiskhide # sh disable
MagiskHide: Stopping MagiskHide daemon
MagiskHide: Killing com.google.android.gms.unstable
MagiskHide: Killing org.freeandroidtools.root_checker
i9300:/magisk/.core/magiskhide # sh enable
MagiskHide: Removing dangerous read-only system props
MagiskHide: Killing com.google.android.gms.unstable
MagiskHide: Killing org.freeandroidtools.root_checker
MagiskHide: Starting MagiskHide daemon
i9300:/magisk/.core/magiskhide #

This is the full log file of Magisk Hide after starting and the terminal commands:

** Magisk post-fs mode running...
** Magisk post-fs-data mode running...
* Running post-fs-data.d
* Loading core props
* Preparing modules
* Stage 1: Mount system and vendor mirrors
* Stage 2: Mount dummy skeletons
* Stage 3: Mount module items
* Stage 4: Execute module scripts
* Stage 5: Mount mirrored items back to dummy
** Magisk late_start service mode running...
* Linking binaries to /sbin
* Starting MagiskSU
* Running service.d
* Starting MagiskHide
MagiskHide: Moving and re-linking /sbin binaries
MagiskHide: Removing dangerous read-only system props
MagiskHide: resetprop by nkk71 & topjohnwu
Initializing...
Modify data structure: 'ro.debuggable'='0'
Existing property: 'ro.debuggable'='1'
Recheck property: 'ro.debuggable'='0'
Done!
MagiskHide: Killing com.google.android.gms.unstable
MagiskHide: Killing org.freeandroidtools.root_checker
MagiskHide: Starting MagiskHide daemon
MagiskHide: Update process/package list:
MagiskHide: [com.google.android.gms.unstable]
MagiskHide: [org.freeandroidtools.root_checker]
Zygote(0) ns=
MagiskHide: com.google.android.gms.unstable(PID=4537 ns=[0 4537 10032 com.google.android.gms.unstable service com.google.android.gms/.droidguard.DroidGuardService]
)
MagiskHide: Stopping MagiskHide daemon
MagiskHide: Killing com.google.android.gms.unstable
MagiskHide: Killing org.freeandroidtools.root_checker
MagiskHide: Removing dangerous read-only system props
MagiskHide: Killing com.google.android.gms.unstable
MagiskHide: Killing org.freeandroidtools.root_checker
MagiskHide: Starting MagiskHide daemon
MagiskHide: Update process/package list:
MagiskHide: [com.google.android.gms.unstable]
MagiskHide: [org.freeandroidtools.root_checker]
Zygote(0) ns=
MagiskHide: Update process/package list:
MagiskHide: [com.google.android.gms.unstable]
MagiskHide: [org.freeandroidtools.root_checker]
MagiskHide: Update process/package list:
MagiskHide: [com.google.android.gms.unstable]
MagiskHide: [org.freeandroidtools.root_checker]
MagiskHide: Update process/package list:
MagiskHide: [com.google.android.gms.unstable]
MagiskHide: [org.freeandroidtools.root_checker]
MagiskHide: Update process/package list:
MagiskHide: [com.google.android.gms.unstable]
MagiskHide: [org.freeandroidtools.root_checker]

The unmount lines are still missing. :/