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My laptop came with Windows 8 pre-installed and uses UEFI (the successor to BIOS) by default. It has been working fine for me for a few months. I decided to install Ubuntu with the goal of a conventional dual-boot setup. I disabled Windows 8's Secure Boot and Fast Startup features to avoid any problems these might cause and shrunk my primary partition by 13 GB from within Windows 8 so that there would be some free space in which to install Ubuntu. I downloaded Ubuntu 12.04.3 on a separate Linux machine and used the ISO file to create a bootable USB drive with Startup Disk Creator. Then I booted my Windows 8 laptop from the USB drive, and successfully installed Ubuntu in the previously allocated free space. Then, dumb me, I immediately forgot my new password. When I reboot my machine it always brings me to Ubuntu without any prompts. I tried entering recovery mode to reset my Ubuntu password, but when I try pressing or holding the left Shift key at any point during the boot sequence, the boot sequence simply continues uninterrupted. The page about recovery mode linked to in the previous sentence says that if I restart (as opposed to power down and power back on), I should meet with a prompt to enter recovery mode, but I don't. Any suggestions that would (a) enable me to boot Windows 8, (b) enable me to recover my password, and/or (c) enable me to re-install Ubuntu completely would be greatly appreciated. I have read that running Boot Repair would enable me to boot Windows 8, but as far as I understand that requires super user privileges (sudo).

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marked as duplicate by Braiam, Warren Hill, guntbert, Luis Alvarado Sep 27 '13 at 17:46

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

up vote 1 down vote accepted

If standard UEFI, you should just be able to go into UEFI menu and choose to boot Windows.

Some UEFI systems need escape rather than left shift key to get grub menu. You can also immediately after UEFI/BIOS press down arrow once. Timing may be important, but grub menu remembers key press after BIOS but before menu appears. Once past menu then it will not matter.

You can run Boot-Repair from your installer, and chroot into your system to make just about any repair.

But is just a new install, it might be easier to just reinstall. Either delete existing partition and use install into unallocated or use manual install Something Else and choose the existing / (root) partition for new /.

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Thank you, oldfred. The solution for me turned out to be pressing escape rather than the left shift key to reach the grub menu. From there I went into "System Setup," booted from my USB drive, and completely reinstalled Linux, erasing the existing installation. – user196444 Sep 28 '13 at 6:08

Oldfred's suggestions are good. One more: Prepare a USB flash drive or CD-R version of my rEFInd boot manager. (The linked-to page includes download links for image files for both USB flash drive and CD-R versions.) When you boot with that image, you should be able to boot both Windows and Linux. If you highlight the Linux option and hit F2 or Insert, you'll get a submenu that should let you boot into single-user mode; or if you hit F2 or Insert again, you'll be able to edit the kernel's boot options in any way you like. With any luck you'll then be able to change your root password. If you like rEFInd, you can install it to your hard disk by installing the Debian package version. If not, you'll need to adjust your GRUB configuration to make it give you a Windows option by running Boot Repair or by making changes manually.

Yet another option to get into Linux: Boot a Linux emergency disk, mount the Ubuntu partition, and edit the /etc/shadow file on that partition. You can then empty the password field for your account, which should enable you to log in with an empty password. Once in, reset your password immediately!

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