I have a laptop running only Ubuntu, but now for some reason I needed Windows so I installed it and everything else works but Grub. How do I get my computer dual booting?
When I installed Ubuntu, I can remember that I needed to create password to Secure boot.
I tried to update Grub but the menu where you can choose Ubuntu/win doesn't appear.
1- Disable fast startup in windows
2- After installing Windows, go to your motherboard firmware and put Ubuntu first and save the settings.
3-
sudo os-prober
sudo update-grub
Note: My English is very bad. :)
I tried updating grub, as well as editing my /etc/grub.d/40_custom and /etc/default/grub but it didn't help.
Then the solution was simply to disable the "fast boot" option in bios. That made the boot list appear. Fast boot disables peripherals and reduce the system capability at boot time in order to get the operating system up asap. You don't need that in your case.
If neither grub update nor bios work, try Windows diagnostics to restore Windows to the last restore point, which would date mostly to a week earlier (Windows creates restore points regularly as far as I can tell).
Most of you would know how to restore, but in case someone doesn't here are the steps:
1- Boot into Windows Installation Disk,a USB disk or compact disk (i.e. CD).
2- Once you get to language-date-keyboard page, click "Next".
3- On the next page, there are "Install" in the center, and "repair your computer" on the left bottom corner. Click "repair your computer".
4- Next page is called "Choose an option". click on "Troubleshoot".
5- Next page is called "Advanced options". click on "System Restore".
6- Then select Windows 10 or whatever you have as OS on the following page.
7- Finally, you get the system restore points. Select the last one and start the restoration.
8- Before you start restoration, you can click "scan affected programs". Usually, no program will be affected but still you can check.
Restart you PC and that's it.
