Linux Won't Boot: How to Diagnose and Fix It
Diagnose and fix the most common boot problems when Linux won't start.
Take a breath — in the vast majority of cases, both the problem and your data have a solution. The first thing is to identify exactly where it fails, because each symptom points to a different cause.
A boot or hardware problem
It doesn't even reach the system selector.
Follow our specific GRUB guide
Follow our black screen guide
Access your files even if the system won't boot
Boot from a Live USB (the same one you used to install, or any recent distribution) → "Try without installing" → from there you can access the file manager, see your hard drive, and copy what matters to an external disk — your data is still there, no matter what is failing at boot.
Tip: always keep a bootable Linux USB stored away — it is your emergency kit for any future boot problem, and it also works for rescuing data from a Windows machine that won't boot.
A kernel panic (Linux's "BSOD")
If the system shows a fatal error message and stops completely (not just a plain black screen), that is a kernel panic — boot with an earlier kernel from GRUB's advanced options to confirm whether the problem is specific to the most recent kernel.
Frequently asked questions
Will I lose my files if Linux won't boot?
In most cases, no — by booting from a Live USB you can access your hard drive and copy your important files, even while the main system won't boot.
How do I know if it's a GRUB problem or a black screen problem?
If the operating system selection menu (GRUB) never appears or fails when choosing Linux, it is a GRUB problem. If GRUB works but it then stays black, that is a different problem, usually graphics drivers.