[Magisk] shashank1094:
I installed Magisk a while back and it was were great, few days back a OTA update was available for my custom rom so I installed it and after that magisk was automatically removed and now I am unable to install it again here are the logs of installation and my specs .

Phone - Redmi Note 4

LOGS :

I:operation_start: 'Flashing'
Installing zip file '/sdcard/Download/Magisk-uninstaller-20180328.zip'
Checking for Digest file...
Skipping Digest check: no Digest file found
I:Update binary zip
I:Zip does not contain SELinux file_contexts file in its root.
I:Legacy property environment not used in updater.
Archive: /sdcard/Download/Magisk-uninstaller-20180328.zip
inflating: META-INF/com/google/android/update-binary
inflating: META-INF/com/google/android/updater-script
inflating: arm/magiskboot
inflating: arm64/magiskboot
inflating: chromeos/futility
inflating: chromeos/kernel.keyblock
inflating: chromeos/kernel_data_key.vbprivk
inflating: magisk_uninstaller.sh
inflating: util_functions.sh
inflating: x64/magiskboot
inflating: x86/magiskboot
inflating: META-INF/MANIFEST.MF
inflating: META-INF/CERT.SF
inflating: META-INF/CERT.RSA
************************
Magisk Uninstaller
************************
- Mounting /system, /vendor
mount: can't find /vendor in /etc/fstab
! Cannot mount /vendor
- Unmounting partitions
Updater process ended with ERROR: 1
I:Install took 3 second(s).
Error installing zip file '/sdcard/Download/Magisk-uninstaller-20180328.zip'
Updating partition details...
I:Data backup size is 8326MB, free: 10027MB.
I:Unable to mount '/sdcard1'
I:Actual block device: '', current file system: 'auto'
I:Unable to mount '/usb-otg'
I:Actual block device: '', current file system: 'auto'
...done
I:Set page: 'flash_done'
I:operation_end - status=1
I:Set page: 'clear_vars'
I:Set page: 'install'
I:Set page: 'flash_confirm'
I:Set page: 'flash_zip'
I:operation_start: 'Flashing'
Installing zip file '/sdcard/Download/Magisk-v16.0.zip'
Checking for Digest file...
Skipping Digest check: no Digest file found
I:Update binary zip
I:Zip does not contain SELinux file_contexts file in its root.
I:Legacy property environment not used in updater.
Archive: /sdcard/Download/Magisk-v16.0.zip
inflating: META-INF/com/google/android/update-binary
inflating: META-INF/com/google/android/updater-script
inflating: addon.d/99-magisk.sh
inflating: arm/magiskboot
inflating: arm/magiskinit
inflating: arm64/magiskboot
inflating: arm64/magiskinit
inflating: chromeos/futility
inflating: chromeos/kernel.keyblock
inflating: chromeos/kernel_data_key.vbprivk
inflating: common/boot_patch.sh
inflating: common/magisk.apk
inflating: common/util_functions.sh
inflating: x64/magiskboot
inflating: x64/magiskinit
inflating: x86/magiskboot
inflating: x86/magiskinit
inflating: META-INF/MANIFEST.MF
inflating: META-INF/CERT.SF
inflating: META-INF/CERT.RSA
************************
* Magisk v16.0 Installer
************************
- Mounting /system, /vendor
mount: can't find /vendor in /etc/fstab
! Cannot mount /vendor
- Unmounting partitions
Updater process ended with ERROR: 1
I:Install took 2 second(s).
Error installing zip file '/sdcard/Download/Magisk-v16.0.zip'
Updating partition details...
I:Data backup size is 8326MB, free: 10027MB.
I:Unable to mount '/sdcard1'
I:Actual block device: '', current file system: 'auto'
I:Unable to mount '/usb-otg'
I:Actual block device: '', current file system: 'auto'
...done
I:Set page: 'flash_done'
I:operation_end - status=1
I:Set page: 'clear_vars'
I:Set page: 'install'
I:Set page: 'flash_confirm'
I:Set page: 'flash_zip'
I:operation_start: 'Flashing'
Installing zip file '/sdcard/Download/Magisk-v15.3.zip'
Checking for Digest file...
Skipping Digest check: no Digest file found
I:Update binary zip
I:Zip does not contain SELinux file_contexts file in its root.
I:Legacy property environment not used in updater.
Archive: /sdcard/Download/Magisk-v15.3.zip
inflating: META-INF/com/google/android/update-binary
inflating: META-INF/com/google/android/updater-script
inflating: addon.d/99-magisk.sh
inflating: arm/magiskboot
inflating: arm/magiskinit
inflating: arm64/magiskboot
inflating: arm64/magiskinit
inflating: chromeos/futility
inflating: chromeos/kernel.keyblock
inflating: chromeos/kernel_data_key.vbprivk
inflating: common/boot_patch.sh
inflating: common/magisk.apk
inflating: common/util_functions.sh
inflating: x64/magiskboot
inflating: x64/magiskinit
inflating: x86/magiskboot
inflating: x86/magiskinit
inflating: META-INF/MANIFEST.MF
inflating: META-INF/CERT.SF
inflating: META-INF/CERT.RSA
************************
* Magisk v15.3 Installer
************************
- Mounting /system, /vendor
mount: can't find /vendor in /etc/fstab
! Cannot mount /vendor
- Unmounting partitions
Updater process ended with ERROR: 1
I:Install took 3 second(s).
Error installing zip file '/sdcard/Download/Magisk-v15.3.zip'
Updating partition details...
I:Data backup size is 8326MB, free: 10027MB.
I:Unable to mount '/sdcard1'
I:Actual block device: '', current file system: 'auto'
I:Unable to mount '/usb-otg'
I:Actual block device: '', current file system: 'auto'
...done
I:Set page: 'flash_done'
I:operation_end - status=1
I:Set page: 'clear_vars'
I:Set page: 'install'
I:Set page: 'main'
I:Set page: 'clear_vars'
I:Set page: 'main2'
I:Set page: 'advanced'
I:Set page: 'copylog'
I:Set page: 'action_page'
I:operation_start: 'Copy Log'
I:Copying file /tmp/recovery.log to /data/media/0/recovery.log

SPECS :

Android version : 8.1.0

Cardinal AOSP version : 5.5

Kernel version : 3.18.104-Feather (gcc version 4.9.x 20150123(prerelease)(GCC)) adesh15@reactor #1 Wed Apr 11 15:04:05 UTC 2018

SELinux status : Permissive