I guess that ‘memtest’ is the third boot entry inside your grub menu - try changing GRUB_DEFAULT=2 to 0, 1, or saved, the latter will boot whatever was chosen last.
You can edit the file with sudo nano /etc/default/grub
Maybe make a backup first: sudo cp /etc/default/grub /etc/default/grub.bak
The default is windows 10. This was working before grub was gone.
Besides now in terminal, pacman -Syu grub command won’t work
Sometime an error message pops saying /mnt unmounted.
Yes it was like that before I booted with windows 10 recovery usb and run bootrec /fixmbr command. So grub is removed from mbr but I can’t find a way to restore.
That’s all right. Thank you anyway. I appreciate all the members who tried to help me.
I think a reinstalling is the easiest way since I don’t have much personal data to back up on manjaro.