Your PC powers on, the fans spin, and then everything stalls on a message saying no bootable device can be found. Windows refuses to load, and you are left staring at a black screen or a blinking cursor with no clear way forward. The good news is that most of these failures trace back to damaged boot files, a bad update, or disk errors, and Windows ships with built-in repair tools that can address every one of those without sending you to a repair shop. Work through the steps below in order, starting with the safest automatic option, and only move to the command line if the simpler fixes come up short.
One thing to keep in mind before you start: if your drive is protected by BitLocker, several of these recovery steps will ask for your BitLocker recovery key. Have it ready so you are not stuck halfway through.
Getting Into the Windows Recovery Environment First
Almost every fix here lives inside the Windows Recovery Environment, known as WinRE. When a PC cannot start, Windows will often open WinRE on its own after repeated failed startup attempts, dropping you straight onto the recovery screen.
If Windows still manages to start normally, you can open WinRE from within the system. On Windows 11, go to Settings > System > Recovery > Advanced startup > Restart now. On Windows 10, the path is Update & Security > Recovery > Advanced startup > Restart now. From the sign-in screen, you can also hold Shift while selecting Power > Restart.
Should the PC refuse to reach WinRE at all, boot from a USB recovery drive or from Windows installation media created with the official Media Creation Tool, then choose Repair your computer. With WinRE open, you are ready to start fixing.
Let Startup Repair Do the Work Automatically
This is the easiest and safest place to begin because it requires no commands and makes no risky changes. Startup Repair scans for common boot problems, including missing or damaged system files and corrupted Boot Configuration Data, then fixes what it can on its own.
- 1.In WinRE, select Troubleshoot > Advanced options > Startup Repair.
- 2.Select Restart and let the tool run its diagnosis.
- 3.When it finishes, power the PC on to see if Windows starts normally.
Startup Repair attempts to fix common boot problems automatically, so give it a full chance to complete before assuming it failed. If you want to see what it found, it writes a log to %windir%\System32\LogFiles\Srt\Srttrail.txt. Remember that a BitLocker-protected device will ask for your recovery key during this process.
Roll Back a Recent Update That Broke the Boot
If the boot failure started right after a Windows update installed, the update itself is a strong suspect. WinRE lets you remove the most recent update without touching the rest of your system.
- 1.In WinRE, select Troubleshoot > Advanced options > Uninstall Updates.
- 2.Choose either Uninstall latest quality update or Uninstall latest feature update, depending on what was installed.
- 3.Let the removal finish, then restart and test the boot.
One word of caution here: if the update in question was a security update, understand the risks before removing it, since doing so can leave your system more exposed. Uninstall it only when you have good reason to believe it caused the boot failure.
Use Safe Mode to Catch a Bad Driver or Program
Safe Mode starts Windows with only a minimal set of drivers, which makes it a clean way to tell whether a recently added driver or program is at fault. If the PC boots successfully in Safe Mode, the problem almost certainly lives in something you installed recently.
- 1.In WinRE, select Troubleshoot > Advanced options > Startup Settings > Restart.
- 2.When the Startup Settings screen appears, press 4 or F4 for Safe Mode.
- 3.For internet access while troubleshooting, press 5 or F5 for Safe Mode with Networking instead, or press 6 or F6 for Safe Mode with Command Prompt.
Once inside Safe Mode, you can remove the most recently installed driver or software and then restart normally to confirm the fix. As with the other recovery paths, a BitLocker-enabled drive will require your recovery key to proceed.
Rebuild the Boot Record and BCD With bootrec
When the screen is black with a blinking cursor, or you see messages such as "Boot Configuration Data (BCD) missing or corrupted", "Operating system Missing", "Boot sector missing or corrupted", or "Bootmgr missing or corrupted", the boot loader itself needs repair. The bootrec commands handle this directly.
Open a command line first: in WinRE, go to Troubleshoot > Advanced options > Command Prompt. If you booted from installation media, you can press Shift+F10 to open one. To repair the boot codes, run these two commands in order:
- 1.Run
BOOTREC /FIXMBRto repair the master boot code. - 2.Run
BOOTREC /FIXBOOTto write a new boot sector to the system partition.
If the trouble is with the BCD store specifically, run Bootrec /ScanOS first to scan all disks for installations and show entries that are not in the BCD store. When you need to rebuild the store, the documented sequence is below. Backing up the existing store first, as the first command does, is the built-in safeguard before you rename and rebuild it.
- 1.Run
bcdedit /export c:\bcdbackupto back up the current store. - 2.Run
attrib c:\boot\bcd -r -s -hto clear the file attributes. - 3.Run
ren c:\boot\bcd bcd.oldto rename the existing store. - 4.Run
bootrec /rebuildbcdto rebuild the Boot Configuration Data store.
Restart after each method so you can test whether that step alone resolved the problem before moving on.
Scan the Disk for Errors With chkdsk
File-system corruption and bad sectors on the drive can also stop Windows from booting. Boot-troubleshooting guidance uses chkdsk /f /r to repair file-system errors and to locate and recover readable data from bad sectors. The /r switch already includes the work that /f does.
From a WinRE or installation-media Command Prompt, run chkdsk /f /r. You can also target a specific drive when needed; for example, chkdsk d: /f checks drive D and fixes errors on it.
Two things to expect: running chkdsk requires local Administrators membership, and if the volume is currently in use, Windows will offer to check it on the next restart instead of running immediately. Let it run through completely, as a full scan of a large or failing drive can take a while.
Repair Corrupted System Files With DISM and SFC
If you suspect that core Windows system files are damaged, the repair order matters: run DISM before SFC. DISM repairs the Windows component store, which SFC then draws on to fix protected system files.
When Windows boots far enough to open it, launch an elevated Command Prompt by typing cmd in Search, right-clicking Command Prompt, and choosing Run as administrator. Then run the repairs in this order:
- 1.Run
DISM.exe /Online /Cleanup-image /Restorehealthand wait for the message "The operation completed successfully". - 2.Run
sfc /scannowto scan and repair protected system files.
When you are fixing an offline Windows that will not boot at all, do this from a WinRE Command Prompt using the documented offline form: SFC /Scannow /OffBootDir=C:\ /OffWinDir=C:\Windows. That tells the tool which boot drive and Windows directory to repair while the system is offline.
If you would rather be guided through these boot problems interactively, Microsoft also offers a Virtual Agent for boot issues, linked from its Windows startup issues troubleshooting page.
Frequently Asked Questions
Which fix should I try first?
Start with Startup Repair. It is the easiest and safest option because it diagnoses and fixes common boot problems, including missing system files and corrupted Boot Configuration Data, without requiring any commands or risky manual changes. Reach it in WinRE through Troubleshoot > Advanced options > Startup Repair.
How do I open the Windows Recovery Environment if my PC will not boot?
Windows will often open WinRE on its own after repeated failed startups. If it does not, boot from a USB recovery drive or from Windows installation media made with the official Media Creation Tool, then choose Repair your computer. When Windows can still start, you can also reach WinRE from Settings > System > Recovery > Advanced startup on Windows 11, or by holding Shift while selecting Power > Restart from the sign-in screen.
Will I need my BitLocker recovery key?
Yes, if your drive is protected by BitLocker. Startup Repair, Safe Mode, and other recovery steps will prompt for the BitLocker recovery key, so have it on hand before you begin so the process is not interrupted partway through.
Should I run DISM or SFC first?
Run DISM before SFC. Use DISM.exe /Online /Cleanup-image /Restorehealth first and wait for "The operation completed successfully", then run sfc /scannow. DISM repairs the component store that SFC relies on to fix protected system files.
Is it safe to uninstall a Windows update to fix booting?
It can help if the boot failure began right after an update, and WinRE lets you remove the latest quality or feature update through Troubleshoot > Advanced options > Uninstall Updates. Be careful with security updates, though; understand the risks before removing one, since doing so can leave your system more exposed.
