Facing issues after installing 2026-03 Security Update (KB5079473) (26200.8037)

Question

Facing issues after installing 2026-03 Security Update (KB5079473) (26200.8037)

ChandraMani 100

After installing 2026-03 Security Update (KB5079473) (26200.8037) almost all apps in my pc, including MS Office, Samsung apps, calculator, PrintScreen, Snipping tool, notepad, etc. have stopped working. Fingerprint login option is gone. The update cannot be rolled back or uninstalled. Cannot login command prompt as Administrator. Administrator rights to reset and restore PC are all lost. This is terrible. I am using Samsung Galaxy Book 4.

Katherine Jett 5 Reputation points

2026-03-13T13:30:25.9033333+00:00

Did a cloud pc update on chrome browser, and have cloud pc connection problem currently. Ran the Security Update (KB5079473) (26200.8037) and immediately had a connection issue advising the URL parameters were unknown. Internet popping 464 down/39 up, normal for me. Please advise a solution.
Sreyas Suvi 10 Reputation points

2026-03-13T14:45:26.9633333+00:00

I have the same laptop and i have the same issue...If you find a solution please share
Katherine Jett 5 Reputation points

2026-03-13T21:41:42.8733333+00:00

Hoping for a solution Monday, using vpn now to connect to cloud pc for the (KB5079473) (26200.8037) update issue. 03/16/2026-issue is resolved.
sudhakar G 15 Reputation points

2026-03-14T06:32:12.58+00:00

After installing 2026-03 Security Update (KB5079473) (26200.8037) almost all apps in my pc, including MS Office, Samsung apps, calculator, PrintScreen, Snipping tool, notepad, and apps not installing etc. have stopped working. Fingerprint login option is gone. The update cannot be rolled back or uninstalled. Cannot login command prompt as Administrator. Administrator rights to reset and restore PC are all lost. This is terrible. I am using Samsung Galaxy Book 4 intel i3 version.
MomoAT 25 Reputation points

2026-03-14T12:34:29.9866667+00:00
I also have the same issue as well; I can't access to windows apps (even opening a picture is not working), accessing to C:drive is also denied. Accessing to cmd with admin is also denied, also accessing to windows restore is also denied. And no my PC is not Samsung (it is not laptop), and it is MSI.

I do have access to C:drive by using the path on windows explorer.

I also went to safe mode and tried to unistall the quality update and it didn't work (also denied).

I went to start safe mode and opened CMD there and tried all those commands:

takeown /F C:\ /R /D J (J is Ja in german, so the English version would be Y)

icacls C:\ /reset /T /C /Q

icacls C:\ /grant SYSTEM:(OI)(CI)F /T /C

icacls C:\ /grant Administrators:(OI)(CI)F /T /C (Administratoren in german)

icacls C:\ /grant Users:(OI)(CI)RX /T /C (Benutzern = Users in german)

icacls C:\ /inheritance:e (failed terribly)

icacls C:\ /setowner "SYSTEM" /T /C

secedit /configure /cfg %windir%\inf\defltbase.inf /db defltbase.sdb /verbose

secedit /configure /cfg C:\Windows\inf\defltbase.inf /db C:\Windows\security\database\defltbase.sdb /verbose

Nothing has worked. And I am not prepared to reset my PC completely, as it should be really the last trumpf card. So I hope this thread gets enough attention.

Also many people in the comment section has similiar issues https://www.youtube.com/watch?v=7IdWx5NgBzo

Updates (after hours of researching and trying any other options)

Seems there were no solution at all, and I had to reset my PC, except, the fact is, I don't have adminstrator permission to do that; even using safe mode restart. So both resetting options from windows and safe mode restart also denied.

So I had to reset using media creation tool
ChandraMani 100 Reputation points

2026-03-17T09:05:25.3633333+00:00

Microsoft Technical Support promised the patch could come up in 48 hrs. However, it has been 5 days and there is still no sign of any update. It's getting really annoying and I am strongly considering fresh OS re-installation with the hope that it does not run into the same issues.

Debojit Chauhan 90

I had the same problem. These are the steps that has been helpful:

Uninstalled Galaxy Connect, then followed the following steps:

Change Permissions:

*   Open File Explorer, right-click on the C: drive, select Properties, then the Security tab, and Advanced.

*   Click "Change," type "everyone" in the object name field, and click OK.

*   Confirm that the owner is now "Everyone" and click OK.

*   Again, select the C: drive, right-click, go to Properties > Security > Edit.

*   Click "Add," type "Everyone," and click OK.

*   On the Security tab, select "Everyone" and check "Allow" for "Full control."

*   Click OK. If prompted by "Windows Security," click "Yes." If "Error Applying Security" appears, choose "Continue" (this may happen multiple times). Click OK twice.

Answer accepted by question author

4 additional answers

Your answer

Katherine Jett 5 Reputation points

2026-03-13T13:30:25.9033333+00:00

Did a cloud pc update on chrome browser, and have cloud pc connection problem currently. Ran the Security Update (KB5079473) (26200.8037) and immediately had a connection issue advising the URL parameters were unknown. Internet popping 464 down/39 up, normal for me. Please advise a solution.
Sreyas Suvi 10 Reputation points

2026-03-13T14:45:26.9633333+00:00

I have the same laptop and i have the same issue...If you find a solution please share
Katherine Jett 5 Reputation points

2026-03-13T21:41:42.8733333+00:00

Hoping for a solution Monday, using vpn now to connect to cloud pc for the (KB5079473) (26200.8037) update issue. 03/16/2026-issue is resolved.
sudhakar G 15 Reputation points

2026-03-14T06:32:12.58+00:00

After installing 2026-03 Security Update (KB5079473) (26200.8037) almost all apps in my pc, including MS Office, Samsung apps, calculator, PrintScreen, Snipping tool, notepad, and apps not installing etc. have stopped working. Fingerprint login option is gone. The update cannot be rolled back or uninstalled. Cannot login command prompt as Administrator. Administrator rights to reset and restore PC are all lost. This is terrible. I am using Samsung Galaxy Book 4 intel i3 version.
MomoAT 25 Reputation points

2026-03-14T12:34:29.9866667+00:00

I also have the same issue as well; I can't access to windows apps (even opening a picture is not working), accessing to C:drive is also denied. Accessing to cmd with admin is also denied, also accessing to windows restore is also denied. And no my PC is not Samsung (it is not laptop), and it is MSI.

I do have access to C:drive by using the path on windows explorer.

I also went to safe mode and tried to unistall the quality update and it didn't work (also denied).

I went to start safe mode and opened CMD there and tried all those commands:

takeown /F C:\ /R /D J (J is Ja in german, so the English version would be Y)

icacls C:\ /reset /T /C /Q

icacls C:\ /grant SYSTEM:(OI)(CI)F /T /C

icacls C:\ /grant Administrators:(OI)(CI)F /T /C (Administratoren in german)

icacls C:\ /grant Users:(OI)(CI)RX /T /C (Benutzern = Users in german)

icacls C:\ /inheritance:e (failed terribly)

icacls C:\ /setowner "SYSTEM" /T /C

secedit /configure /cfg %windir%\inf\defltbase.inf /db defltbase.sdb /verbose

secedit /configure /cfg C:\Windows\inf\defltbase.inf /db C:\Windows\security\database\defltbase.sdb /verbose

Nothing has worked. And I am not prepared to reset my PC completely, as it should be really the last trumpf card. So I hope this thread gets enough attention.

Also many people in the comment section has similiar issues https://www.youtube.com/watch?v=7IdWx5NgBzo

Updates (after hours of researching and trying any other options)

Seems there were no solution at all, and I had to reset my PC, except, the fact is, I don't have adminstrator permission to do that; even using safe mode restart. So both resetting options from windows and safe mode restart also denied.

So I had to reset using media creation tool
ChandraMani 100 Reputation points

2026-03-17T09:05:25.3633333+00:00

Microsoft Technical Support promised the patch could come up in 48 hrs. However, it has been 5 days and there is still no sign of any update. It's getting really annoying and I am strongly considering fresh OS re-installation with the hope that it does not run into the same issues.
Debojit Chauhan 90 Reputation points

2026-03-18T09:58:09.7366667+00:00

I had the same problem. These are the steps that has been helpful:

Uninstalled Galaxy Connect, then followed the following steps:

Change Permissions:
* Open File Explorer, right-click on the C: drive, select Properties, then the Security tab, and Advanced. * Click "Change," type "everyone" in the object name field, and click OK. * Confirm that the owner is now "Everyone" and click OK. * Again, select the C: drive, right-click, go to Properties > Security > Edit. * Click "Add," type "Everyone," and click OK. * On the Security tab, select "Everyone" and check "Allow" for "Full control." * Click OK. If prompted by "Windows Security," click "Yes." If "Error Applying Security" appears, choose "Continue" (this may happen multiple times). Click OK twice.

Answer 1

Debojit Chauhan 90

Had the same issue.

Took the following steps:

Uninstalled Galaxy connect, then

Change Permissions:

*   Open File Explorer, right-click on the C: drive, select Properties, then the Security tab, and Advanced.

*   Click "Change," type "everyone" in the object name field, and click OK.

*   Confirm that the owner is now "Everyone" and click OK.

*   Again, select the C: drive, right-click, go to Properties > Security > Edit.

*   Click "Add," type "Everyone," and click OK.

*   On the Security tab, select "Everyone" and check "Allow" for "Full control."

*   Click OK. If prompted by "Windows Security," click "Yes." If "Error Applying Security" appears, choose "Continue" (this may happen multiple times). Click OK twice.

ChandraMani 100 Reputation points

2026-03-18T11:02:59.32+00:00

Thank you so much, Debojit. It worked. There are still some issues like the fingerprint sensor is still not detected. Otherwise, the system is completely functional now.
Debojit Chauhan 90 Reputation points

2026-03-20T06:14:36.0933333+00:00

I ran command prompt as an administrator. type "sfc/scannow". let the scan run. Restart and check. It has worked for me.
ChandraMani 100 Reputation points

2026-03-20T10:31:54.62+00:00

Indeed, it worked. :)
Paul Leigh 0 Reputation points

2026-03-26T04:47:25.17+00:00

This answer assumes Windows is accessible. From what I’ve read, most computers are stuck in loop and will not open Windows at all! This update is a fking nightmare! MS fk’d up and needs to come clean!
ChandraMani 100 Reputation points

2026-04-03T06:18:13.9666667+00:00

MS has released KB5085516, an out of turn update, and it appears to have solved the issues. The pc now appears to be back in its default settings. But do remember to uninstall Galaxy Connect beforehand. It appears to be the conflicting app with the update.

Answer 2

ChandraMani 100

Connected with Microsoft Technical Support. They acknowledged the existing issue. Assured that they are working on a solution which hopefully will be out soon. In the meantime, advised others to abstain from installing the problematic update, even though it might not affect all systems. However, it's getting a little impatient. I hope that the Microsoft guys come up with a patch soon.

Sam 0 Reputation points

2026-03-15T04:10:02.37+00:00

Thanks for sharing the update. I am facing same issue as others reported post system update and reboot in my Samsung laptop, lost all access to C drive and as a result none of the applications - MS Office, Snipping tool, WhatsApp application nothing is working. Only Chrome browser is working through which internet access is active. Essentially this is widespread impact not sure how MS published such untested patch in production environment.
Paul Leigh 0 Reputation points

2026-03-26T04:49:12.8433333+00:00

Someone or the group responsible for releasing this update needs to be terminated!
Judi Hosking 0 Reputation points

2026-04-05T06:20:04.77+00:00

Microsoft appears to be having a multitude of problems since they introduced Windows 11. Definitely thinking to reverting to Windows 10. Had no problems with that.

Answer 3

Pieter Van der Hulst 0

Having the same situation. Newly installed Windows 11 - and after the KB5079473 update following issues arise:

Search no longer works
Pressing the Win-logo does not open the side bar
Can't open Settings (or anything related) & as such - unable to uninstall
Updates does not open/show either & as such running updates is not an option (see above)

Unable to uninstall the KB5079473 from Safe Mode :-(

Sorry to say, but this has nothing to do with the type / brand of the disk.

0 comments

Answer 4

DaveM121 863.6K Independent Advisor

This problem seems to be caused by an emerging problem being reported in the March update where the user looses permissions on the C drive, usually on devices with Samsung drives.

1

Start your PC, just as Windows attempts to load (spinning dots), press and hold Power Button for 5 - 10 seconds to perform a Hard Shut Down

Do this twice

On the third start Windows will boot into the Recovery Environment and from there you can access System Repair, Safe Mode, Command Prompt... etc.

In there, should be an option to uninstall that update.

2

If you are unable to uninstall the update, try this method to restore permissions in the C drive, if you can use these steps to open Command Prompt as Administrator.

Click your Start Button, then just type cmd and on the resulting list, right click Command Prompt and select 'Run as Administrator.

Paste this into Command Prompt and press Enter.

icacls C:\ /reset /T /C /L icacls C:\ /grant Administrators:F /T /C

When that command completes, restart your PC and check if that resolves the problems caused by the update.

MomoAT 25 Reputation points

2026-03-14T13:38:15.5266667+00:00
I tried this suggested solution and it didn't work at all. (I am not samsung device user, this is MSI PC)

Those steps I tried:

performing Hard Shut Down as you suggested

I did it thrice as many other online sources implied (twice haven't worked for me)

There is an option to unistall the latest windows quality update, but I got denied access there

Since I was unable to unistall it, I tried your command

After restarting my PC, and no problem has been resolved.

I still have no access to C:drive, got denied access to cmd with admin rights, and I can't access to any application that is installed in C:drive and I can't open task manager or windows applications.
ChandraMani 100 Reputation points

2026-03-14T15:44:13.1+00:00

Tried it but still can't get administrator rights and issues remain unresolved. Account status does show as Administrator. Connected with the Microsoft Technical Support and acknowledged the issue. They are working on a solution which hopefully will be out soon.
Sam 0 Reputation points

2026-03-15T04:13:36.3033333+00:00

Thanks for sharing, I tried the command as you suggested but unfortunately it didn't execute over command prompt with admin privileges in safe mode of laptop. In normal mode for me command prompt is not working/ allowing administrative privilege.
DaveM121 863.6K Reputation points Independent Advisor

2026-03-15T06:29:54.88+00:00

Okay, hopefully they will push out an out-of-band patch to resolve this very soon.
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ChandraMani 100 Reputation points

2026-03-17T16:28:31.58+00:00

Can't get Administrator rights. Even access to drive C is denied.
Ramesh 176.1K Reputation points Volunteer Moderator

2026-03-17T16:30:18.1+00:00

@ChandraMani: Do you have a Samsung device?
ChandraMani 100 Reputation points

2026-03-17T16:51:16.9533333+00:00

Yes, it is Samsung Galaxy Book 4
Ramesh 176.1K Reputation points Volunteer Moderator

2026-03-17T16:53:00.81+00:00

@ChandraMani:

Here you go for the fix.

Recovery steps: Samsung Galaxy Connect or Samsung Continuity Service might cause loss of access to the C: drive - Microsoft Support
Paul Leigh 0 Reputation points

2026-04-03T11:40:37.4966667+00:00

This solution did not work as the update blocked the ability for my HP laptop to get to the bluescreen to run utility tools. I gave up after exhausting several days of no-wins. I took my laptop into Best Buy for technical support (Geek Squad) and they’re even having a difficult time getting my HP back to normal. After all the time lost and being left hung out to dry by Microsoft, I bought a new Macbook yesterday. Leaving Microsoft’s negligence and incompetency for good.
Judi Hosking 0 Reputation points

2026-04-05T06:21:29.28+00:00

I refuse to do any more updates with Microsoft until they pull their fingers out and fix Windows 11 and all it problematic updates

Answer 5

The described behavior after installing KB5079473 matches a known pattern where a problematic Windows security update temporarily causes widespread issues, and the situation later self-corrects when Microsoft revises or reoffers the update.

From the available information, the recommended action is to allow Windows Update to re-check and re-apply updates, as the issue has been observed to self-resolve without manual repair steps in at least one reported case for this same KB (5079473). Specifically:

Ensure the device is connected to the internet and left powered on for an extended period so Windows Update can complete any pending remediation or follow-up updates.
When possible, run Windows Update again from Settings → Windows Update and install any new or reoffered updates related to KB5079473.
After updates complete, restart the device and re-test affected apps and sign-in options.

In the referenced case, KB5079473 eventually installed successfully and the issue resolved without needing additional tools or OS reinstall.

References:

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Facing issues after installing 2026-03 Security Update (KB5079473) (26200.8037)

4 additional answers

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