How to fix UNMOUNTABLE_BOOT_VOLUME on Windows 10

Getting Windows 10 UNMOUNTABLE_BOOT_VOLUME BSOD loop at startup?

Laptop won’t start after a Windows 10 feature update. Frequently getting Unmountable Boot Volume?

You are on the right place here, this post we have different solutions to fix Unmountable Boot Volume BSOD on Windows 10.

Issue: After Windows 10 upgrade getting unmountable boot volume BSOD

I recently upgraded six client Windows 10 v1809 computers to Windows 10 v2004 via WSUS, when the computers restarted I got the BSOD error unmountable boot volume stop 0x000000.

Unmountable Boot Volume Error? The “boot volume” is the system partition of your hard drive that holds the Windows operating system. But If due to any reason when your computer can’t load Windows properly from the system partition this will result startup failure with a BSOD error “UNMOUNTABLE_BOOT_VOLUME” stop 0x000000

Unmountable Boot Volume error usually occurs due to a damaged file system or corrupted Windows files. Again Window update bug, disk drive failure, security software or faulty hardware device or incompatible device driver also cause this Windows 10 BSOD error. Whatever the reason, here some solutions you may apply to fix this Blue Screen error.

Whenever you get windows 10 Blue Screen error at startup, The first thing you have to do is disconnect all external devices such as a printer, scanner, external HDD, USB device etc ( expect keyboard&mouse) then start windows normally.Use Windows Automatic Repair

As we are unable to start access windows 10 normally, we need to access advanced options where you can get various troubleshooting tools like startup repair, safe mode, advanced command prompt and more. Lets first access advanced options and perform startup repair.

• First of all boot windows from an installation media, (If you don’t have here check how to create a windows 10 bootable USB/DVD).

• Let Windows start from your USB/DVD until it loads up, and click the next button.

• You’ll see the Install now screen click repair your computer in the bottom-left instead.

• On the following screen, select troubleshoot to get a list of advanced options.

• Choose startup repair and choose the target OS, Windows 10 (or your version).

• The repair will be started immediately.

• Please wait patiently for the process to be finished.

Once it’s done, exit the installer and try to boot your computer normally.

Repair the Master Boot Record

The Master Boot Record (MBR) contains information about where and how your operating system is located your hard drive and helps it load properly when you turn your computer on. If this becomes corrupted, it can lead to an unmountable boot volume error.

• Again access advanced options from your Windows 10 install media

• Select repair your computer > troubleshoot.

• This time, on the advanced options screen, choose command prompt.

Perform command below to repair MBR, rebuild BCD and fix boot manager problems

• bootrec /fixmbr

• bootrec /fixboot

• bootrec /rebuildbcd

• bootrec /scanos

• After complete these commands type exit to leave the command prompt,

• Then reboot your system and check this time windows started normally

Run the Ckhdsk Command

If an automatic repair and MBR repair didn’t solve your problem, then boot into safe mode from advanced options and run Chkdsk command to check and fix disk drive errors.

• When windows start on safe mode search for cmd,

• Right click on the command prompt and select run as administrator.

• Then type command chkdsk C: /f /r

Note: Here C: is your system drive letter. The /r flag locates any bad sectors on your disk and fixes those errors and /f Fixes errors on the disk.

• Chkdsk may ask you to run next time the system restarts.

• If it does, enter Y for yes and reboot to start it.

• This will start the scanning and repairing process for drive C:

• Wait until 100% complete the scanning process

• After that restart windows and check may this helps to fix the windows 10 BSOD error.

Run SFC utility and DISM command

Run system file checker its another effective solution (scan and restore missing corrupted system files ) you must apply if windows fail to fix unmountable boot volume after applying startup repair, repair BCD/MBR, check drive errors.

• Again open the command prompt (admin) on safe mode

• Type command sfc /scannow and hit the enter key.

• This will scan for corrupted system files If found any the SFC utility will restore them from a special folder located on %WinDir%\System32\dllcache.

• Wait until 100% complete the scanning process

• After that restart windows and check, You never get a BSOD error if missing corrupted system files causing the issue.

If system file checker scan results windows resource protection found corrupt files but was unable to fix some of them. Then run the DISM command “dism.exe /online /cleanup-image /restorehealth” which repair the system image and allow SFC to do its job.

Run Memory Diagnostic Tool

Sometimes this Unmountable Boot Volume Blue Screen STOP: 0x000000ED can happen due to bad memory so for this try Run Memory Diagnostic Tool.

Run the Hardware and Device troubleshooter from settings -> update & Security -> Troubleshoot -> select Hardware and Device and run the Troubleshooter for check and make sure any faulty hardware device not causing the BSOD error at startup.

Also Recently installed Third-party applications to check and make sure application compatibility not causing the issue. Open Control Panel -> All Control Panel Items -> Programs and Features. Here select the recently installed Application and click uninstall Restart windows and check.

Open device manager and update/reinstall the display driver with the latest version. As users report reinstall the display driver mostly fix maximum blue screen errors on windows 10.

If the problem started for you after installing windows 10 version 1903 and applying the above these solutions didn’t fix the problem then may the windows update bug causing the issue. As Microsoft recommends Roll back windows 10 to the previous version, Defer windows update and wait for Microsoft to fix the bug and the OS get stable.

Performing the above solution didn’t fix the problem, Still, windows restart with BSOD error then its time to utilize the system restore feature, which reverts windows configuration to a previous working state without affecting any files.

Did these solutions help to resolve Unmountable Boot Volume BSOD Error?

Windows 10 in S mode: Pros and cons

S mode is a Windows 10 feature that improves security and boosts performance, but at a significant cost. Find out if Windows 10 in S mode is right for your needs.

In 2017, Microsoft added a new feature to its Windows 10 operating system: S mode, a stripped-down, tightly-locked, and low-end PC friendly way to run Windows 10. There are a lot of good reasons to put a Windows 10 PC in S mode, including:

• It's more secure because it only allows apps to be installed from the Windows Store;

• It's streamlined to eliminate RAM and CPU use; and

• Everything a user does in it is automatically saved to OneDrive to free up local storage.

If that sounds like another OS you're familiar with, you're not wrong--it's a lot like Google's ChromeOS for its Chromebooks. Microsoft even made Windows 10 in S mode to run on ARM processors, so it's intentionally designed to work well on hardware that wouldn't normally run Windows 10 very smoothly.

Performance and security improvements always come at a cost though, and Windows 10 in S mode is no different. If you're considering a new Windows 10 PC, especially a Surface device (these often ship with Windows 10 in S mode standard), be sure you know what you're getting yourself into before meeting with disappointing surprises.

Pro: Windows 10 in S mode is more secure

There's one major reason why Windows 10 in S mode is more secure: You can only install apps from the Microsoft Store. Think of it like the Chrome OS Web Store, iOS App Store, or Google Play--you have to go to one of those locations to get apps for your device, which means Apple, Google, or Microsoft has vetted it for safety and performance.

Microsoft also restricts antivirus software to its own built-in Windows Defender Security Center, and has stated in its Windows 10 S FAQ that "the only antivirus software known to be compatible with Windows 10 in S mode is the version that comes with it." 

Like other OSs managed top to bottom by the manufacturer, it's interoperability is its strength when it comes to keeping you safe.

Con: Security comes at the cost of usability

The resilience of Windows 10 in S mode comes with several drawbacks.

As mentioned above, you can only install apps from the Microsoft Store. That may not seem like a big deal at first (because surely the apps you need will be in the Microsoft Store), but there are a lot of things professional users need that are downloaded from the web or installed using other app management platforms. 

S mode means no Adobe software, no Apple apps, no non-Microsoft video conferencing apps, and no third-party security software--in short, if it comes to a Windows PC via a third party it doesn't come to S mode at all.

That includes web browsers and that's a deal killer for many people. S mode users are stuck with Edge as their browser and Bing as their default search engine. To further restrict browsing matters, even if Chrome or Firefox were installed on an S mode computer (neither are available in the Microsoft Store) it couldn't be set as the default browser, nor can the default search engine be changed. 

Pro: Windows 10 in S mode is ideal for large-scale enterprise and education deployments

In offering S mode, Microsoft is trying to compete for two markets, both of which are currently dominated by Chromebooks: Students and large enterprises with lots of machines to manage.

Schools and businesses have hardware needs in common--they need to deploy a lot of machines to a lot of people, they need them locked down so users don't get infected with malware or lose a machine filled with sensitive data, and they need them to be cheap.

S mode was built to address those needs, all while being a familiar interface that most computer users have worked with at least once in their lives. Windows 10 S mode looks and feels no different than using Windows 10 home, Pro, or Enterprise, but it allows administrators to keep a short leash on users. 

Windows 10 in S mode is also built to run on far lower end PCs, without bogging down their hardware, meaning a simple PC deployment for a user that only needs access to Office apps and a web browser can be more affordable for businesses and schools than ever before, and is perfect for business and education users.

Pro: It's easy to switch to a full version of Windows 10

If you bought a Windows 10 PC with S mode installed, you may have been surprised by what you couldn't do. Don't be dismayed--you aren't stuck with S mode. In fact, you can switch out of S mode at any time. 

To switch from S mode to the full version of Windows 10 hiding behind it, navigate to Settings | Update And Security | Activation. In the Activation menu, look for Switch To Windows 10 Pro (or Home--you'll see one of the two depending on what version of Windows 10 your computer has). 

Clicking Switch will open the Microsoft Store and prompt you to "Get" the full version, akin to installing an app. Once you do that, your PC will switch over to its full version of Windows 10 and you'll be free to install whatever apps you wish.

Be forewarned: Switching out of S mode is a one-way street. Once you turn S mode off, you can't go back, which could be bad news for someone with a low-end PC that doesn't run a full version of Windows 10 very well.

The other trade-off to deactivating Windows 10 S mode is that you're taking security into your own hands, and without installation restrictions, it's much easier to find yourself infected with malware. As always, be sure you double-check that switching to the full version of Windows 10 is necessary for your needs and look online to find out if your computer meets hardware requirements to run the full version.