After installing Lubuntu in dual-boot with windows 10, I cannot access windows anymore

Question

I installed the latest version of Lubuntu (which I also want to change to normal Ubuntu in the end) on a LENOVO ideapad (don't know how to get details on the laptop on lubuntu) but I cannot access Windows anymore. I don't have any disc or anything because the laptop was ordered from internet and has no shop I can go to neither any recovery disc so. I don't want to erase windows neither change it also because it is still under warranty.

I would like to erase lubuntu which has no audio interface and also I believe is way too minimal, be able to access windows 10 again and install Ubuntu on a different partition in dual boot. (so far I believe they two OS are on the same partition) Any advice?

So far, I managed to uninstall Lubuntu and install Ubuntu. I still have the problem with Windows, I started following the instructions given below. First of all I realised it's windows 8 so I assume the UUID is different? Second, do I have to copy and paste the window or change the UUID ...and as for the position, I don't see where I can type ('hdo,msdos1').

Thanks for your help so far. If a boot-repair is better I can try again now that I can work from Ubuntu directly.

Answer 1

You will be better off in the future if primary OS is backed up prior to the installation of another.

First, preferably, we have to discover a path that let us boot you into Windows.

Assuming that Lubuntu filesystem has not overwritten any bit of Windows (highly probable) and GRUB is installed with Lubuntu on default you can let os-prober do the job.

To be on the safe side, change /etc/default/grub settings:

GRUB_DEFAULT=saved
GRUB_SAVEDEFAULT=true
# GRUB_HIDDEN_TIMEOUT=0
GRUB_HIDDEN_TIMEOUT_QUIET=true
GRUB_HIDDEN=-1
GRUB_TIMEOUT=100
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX=""
GRUB_DISABLE_OS_PROBER=false

Type into CLI:

# sudo update-grub

Check whether grub.cfg resides in /boot/grub/

If positive, try:

# sudo grub-mkconfig -o /boot/grub/grub.cfg

If os-prober (which should be on default turned on) found UUID of Windows bootloader partition, you can reboot the system, choosing Windows when dialogue appears just after BIOS.

If os-prober failed, we would manually provide GRUB with location of Windows bootloader partition.

To do this, we have to obtain Windows bootloader partition:

blkid

Probably it is in position of /dev/sda1:

/dev/sda1: UUID="SPX7ZJUBC2EN7FAH" TYPE="ntfs"

Now, as we know UUID, we have to adjust this piece of code:

#!/bin/sh
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.

# Windows 10 Pro 64-bit (loader) (on /dev/sda1)
menuentry 'Windows 10 Pro 64-bit (loader) (/dev/sda1)' --class windows --class os 
$menuentry_id_option 'osprober-chain-SPX7ZJUBC2EN7FAH' {
     insmod part_msdos
     insmod ntfs
     set root='hd0,msdos1'
     if [ x$feature_platform_search_hint = xy ]; then
        search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos1 --hint-efi=hd0,msdos1 --hint-baremetal=ahci0,msdos1  SPX7ZJUBC2EN7FAH
     else
        search --no-floppy --fs-uuid --set=root SPX7ZJUBC2EN7FAH
     fi
     parttool ${root} hidden-
     drivemap -s (hd0) ${root}
     chainloader +1
}
set timeout_style=menu
if [ "${timeout}" = 0 ]; then
   set timeout=10
fi
# End of Windows 10 Pro 64-bit (loader) (on /dev/sda1)

Change UUID (SPX7ZJUBC2EN7FAH) and position ('hd0,msdos1') of Windows bootloader everywhere.

Paste code provided into /etc/grub.d/40_custom and save.

Then, once again, put into CLI:

# sudo grub-mkconfig -o /boot/grub/grub.cfg

Reboot.

Before you erase Lubuntu, try to change desktop enviroment for e.g. MATE:

Install MATE how-to

I think it would be enough for enriching your computer experience and would make all functionalities available easier.

Recommended reading:

1. GRUB Manual: 5. Writing your own configuration file, p.17 et seq.
2. GRUB Manual: 5.3. Multi-boot manual config, p.24.
3. GRUB Manual: 29. Invoking grub-mkconfig, p.99.
4. GRUB Manual: 32. Invoking grub-probe, p. 105 et seq.