How to fix
SESSION1 INITIALIZATION FAILED BSOD error
on Windows

My PC keeps crashing with a blue screen that says SESSION1_INITIALIZATION_FAILED. It usually happens right after I turn it on, and I can’t even reach the desktop sometimes. I haven’t installed any new hardware or software recently. Does anyone know what causes this or how to fix it?

Blue Screen of Death (BSOD) errors are a vital part of Windows' protection mechanism. When the system faces a problem it cannot recover from (usually hardware, driver, or core system file problems), it will halt everything and show a blue screen to prevent further damage. While these kinds of errors are frustrating and usually disruptive, they protect by forcing a shutdown before anything worse occurs.

One BSOD that some users encounter is the SESSION1_INITIALIZATION_FAILED error. It typically appears shortly after boot or during the boot of Windows, and it is typically preceded by a STOP code that signals session initialization failure. This one is different from other, more common blue screens triggered by drivers or RAM issues in that it relates to Windows' core components failing to initialize properly.

The name refers to the failure of "Session Manager," an essential Windows service that handles system-level sessions needed during boot. If it can't initialize correctly, the system just can't continue loading. This can happen due to damaged system files, damaged boot records, improperly installed updates, or even problematic hardware, hard drive, or SSD specifically. Occasionally, third-party software that interferes with boot operation (such as antivirus software or system cleaners) can also be the offenders.

In most instances, resolving this error means addressing underlying system corruption or misconfiguration. System restore points and startup repair tools can help, but if those are unavailable, further troubleshooting is in order.

If you have seen the SESSION1_INITIALIZATION_FAILED BSOD, you are not on your own, and while it is a critical error, it's usually fixable. Manual troubleshooting measures will help, but if you're not sure where to start or the error is recurring, you might want to consider using a repair tool such as [d1], which will automatically search for and repair more advanced system-level issues.

Create a bootable Windows USB for another computer [if you can't access Windows normally]

To make Windows Installation Media USB, use another computer to download and set up a bootable USB device with Windows installation files.  The bootable USB device will allow you to access numerous recovery options and undertake necessary repair actions.

• Download Windows 11 Installation media from the official Microsoft website. [Windows 10 version]
• Double-click the MediaCreationTool.exe file to launch it.
• When UAC shows up, click Yes.
• Accept license terms.
• Select Language and Edition (make sure it matches the one you have currently installed) or simply mark the Use the recommended options for this PC and click Next.
• Select the ISO file and click Next.
• Pick the location for your ISO file and wait till all the needed files are downloaded, then click Finish.
• Insert your Windows installation media (USB or DVD) into a malfunctioning PC.

Fix 1. Run Startup Repair

If Windows can’t start properly, using the built-in Startup Repair can fix boot-related file corruption.

• Restart Windows - use the Power or Reset button.
• Once the system starts loading, interrupt the process by pressing and holding the Power button for several seconds - do this two more times, and you should enter Windows Recovery Environment.
• From here, select Troubleshoot > Advanced Options and click Startup Repair.
• Allow the Startup Repair process to run and follow any on-screen instructions.

Fix 2. Run SFC and DISM

Corrupted or missing system files can cause BSOD errors during initialization.

• Open Command Prompt as administrator - from Safe Mode (Troubleshoot > Advanced options > Command Prompt) or recovery options.
• Copy and paste the following command, pressing Enter after:
  sfc /scannow
• Wait till the scan is finished. If Windows finds system file integrity violations, it will attempt to fix them. After this, use the set of the following commands, pressing Enter each time:
  DISM /Online /Cleanup-Image /CheckHealth
  DISM /Online /Cleanup-Image /ScanHealth
  DISM /Online /Cleanup-Image /RestoreHealth
  
• (Note: if you get an error executing this last command, add /Source:C:\RepairSource\Windows /LimitAccess to it and try again).
• Restart your PC in normal mode.

Fix 3. Use Safe Mode to uninstall recent updates

Sometimes, a recent Windows update may cause system conflicts leading to BSODs.

• Access Windows Recovery Environment.
• Go to Troubleshoot > Advanced options.
• Select Go back to the previous build/Uninstall updates (whichever option is available).
• Select your user account and provide the password if required.
• Follow the prompts to revert to the previous build.
• Restart your system.

Fix 4. Perform a System Restore

Restoring your PC to a point before the error started may undo the changes that caused it.

• Access Windows Recovery Environment.
• Go to Troubleshoot > Advanced options.
• From here, pick System Restore.
• Pick the point in time when the problem did not exist and follow the on-screen instructions.
• Your system will restart.

Fix 5. Check disk for errors

A failing hard drive or SSD can trigger initialization errors during boot.

• Open Command Prompt as administrator (via Safe Mode or recovery).
• In the new window, type in the following command and press Enter after:
  chkdsk c: /f
  (Note: use chkdsk c: /f /r /x command if you are using SSD as your primary partition)
• Restart in normal mode once finished.

Fix 6. Reset BIOS/UEFI

Misconfigured BIOS settings can cause low-level initialization failures.

• Restart your PC and enter BIOS (usually by pressing F8, F10, F12, Del, etc.)
• Go to one of the sections that would have an option to reset BIOS (varies depending on your motherboard).
• Select Load optimized defaults or similar.
• Press F10 to save changes and exit.
• Restart the PC and check if it boots normally.

Fix 7. Disconnect external devices

External hardware can sometimes interfere with Windows boot initialization and cause BSODs. Disconnecting them helps rule out hardware conflicts.

• Shut down your PC.
• Unplug all external devices except for keyboard and mouse.
• Turn your PC back on and check if it boots normally.
• If successful, plug in devices one by one to identify the culprit.