How to fix secur32.dll error in Windows?

secur32.dll is a Windows file that programs use to sign in and authenticate securely. A Bad Image window saying it "is either not designed to run on Windows or it contains an error" means Windows found the file but could not load it. Repair Windows files with DISM and SFC first; never download the DLL.

Facts checked on 15 October 2026. Steps written for Windows 11 (25H2 and 26H2) and Windows 10 22H2.

What secur32.dll is and why so many programs need it

secur32.dll belongs to Windows, not to any app. Microsoft's developer documentation names Secur32.dll as the DLL, and Secur32.lib as the library, for the Security Support Provider Interface (SSPI). Programs call it to get a handle to your sign-in credentials and to set up secure, authenticated connections.

File

secur32.dll, the Security Support Provider Interface library

Location

C:\Windows\System32 (the path in the Bad Image window)

Example functions

AcquireCredentialsHandle, used with InitializeSecurityContext and AcceptSecurityContext

Minimum Windows for these functions

Windows Vista and Windows Server 2008, per Microsoft's requirements table

Who loads it

File Explorer (explorer.exe), browsers, mail and network programs, and many apps that sign in or connect securely

Because so much of Windows signs in through it, a damaged secur32.dll rarely breaks only one app. That is why readers see the window from several programs at once, or from explorer.exe right after typing the password.

What the secur32.dll error means

The window is a Windows Bad Image message. It means a program asked Windows to load secur32.dll, Windows found the file, but its content was damaged or not what the loader expects. The text reads like this, as a reader quoted it on Microsoft Q&A:

The Bad Image window (title: explorer.exe - Bad Image)

C:\Windows\system32\secur32.dll
is either not designed to run on Windows or it contains an error.
Try installing the program again using the original installation media
or contact your system administrator or the software vendor for support.

Ignore the advice to install "the program" again. The program in the title only tried to load the file; the damaged file belongs to Windows. Two details in the window decide where you start:

• The status code. Bad Image windows can end with an Error status code. We could not confirm which code the secur32.dll window shows. Our OneDrive Bad Image guide explains what each code means.
• A sister case. The same message for another Windows file is covered in our dxcore.dll guide. The logic is the same: repair Windows, do not replace single files by hand.

What causes the secur32.dll error, from most to least common

Most often the Windows copy of secur32.dll is damaged, for example after a crash or a power cut during an update. Less often the component store that SFC repairs from is damaged too, or malware has changed the file. Rarely the disk itself is failing.

• DISM error 4448. One reader on Microsoft Q&A got secur32.dll Bad Image windows from many apps on Windows 10 22H2. SFC could not fix everything, and DISM stopped at 56.3 % with "Error: 4448 The WOF driver encountered a corruption in the compressed file's Resource Table". The moderator's answer was a repair install.
• Re-registering the DLL. Some pages suggest regsvr32 secur32.dll. Registering a DLL does not change its content, so it cannot repair a damaged file. That method is not on this page.

How to fix the secur32.dll error in Windows

Fix 1 helps most readers. Fix 2 to Fix 6 follow in order of how often they help and how little they cost. If you only get a black screen after sign-in, start with Fix 7 to reach a working desktop or the recovery screen, then come back to Fix 1.

Fix 1. Repair secur32.dll with DISM and SFC

20 to 30 minutesNo riskThe Bad Image window names C:\Windows\system32\secur32.dll, or says the file is missing. This is the first fix for almost everyone.

secur32.dll is a protected Windows file. DISM first repairs the component store Windows keeps its files in, and SFC then replaces a damaged secur32.dll from that store with the right version for your build.

1. Open an elevated command window. Right-click Start and select Terminal (Admin), or type cmd in the search box, right-click Command Prompt and select Run as administrator. Select Yes when Windows asks for permission.

   

2. Run DISM first. Type the command below and press Enter. DISM downloads clean copies of damaged components from Windows Update, so it can take several minutes. Wait until it says The operation completed successfully.

   DISM.exe /Online /Cleanup-Image /RestoreHealth

   

3. Run System File Checker. In the same window, type the command below and press Enter. Do not close the window until the verification reaches 100%.

   sfc /scannow

   

4. Read the result and restart. Compare the last message with the table below this guide, then restart the PC so that repaired files are loaded.

   

These steps were written for Windows 11 24H2 and 25H2. The full page with the other versions and what each result means: Run DISM and SFC to repair Windows system files

Run DISM /RestoreHealth first, then sfc /scannow, then restart. SFC alone can fail when the store is damaged too, which is what happened in the Microsoft Q&A case.

Fix 2. Scan for malware with Microsoft Defender Offline

15 to 60 minutesLow riskThe file breaks again after Fix 1, the path is not System32, or the PC also shows pop-ups, a changed browser or disabled security.

A Microsoft Community volunteer noted that secur32.dll can be damaged by malware, naming the trojan Bladabindi. The offline scan restarts the PC and scans before Windows loads, so malware that hides while Windows runs cannot interfere.

1. Open Windows Security. Select Start, type Windows Security and open the app.
2. Open Virus & threat protection. Select Virus & threat protection. Under Current threats you see when the last scan ran, how long it took and how many files it checked.
3. Run a quick scan. Select Quick scan. If Windows Security thinks a deeper scan is needed, it tells you when the quick scan is done.

   

4. Open Scan options. If the quick scan finds nothing and you still suspect an infection, select Scan options under Current threats.
5. Run a full scan. Select Full scan and start it. It checks every file and program on the device, so it takes much longer than a quick scan. Leave the PC on until it ends.

   

6. Or scan one folder. To check only a download or a USB drive, select Custom scan in Scan options and choose the folder. You can also right-click a file or folder in File Explorer and select Scan with Microsoft Defender. On Windows 11 you may have to select Show more options first.
7. Read Protection history. Go back to the first page of Windows Security and select Protection history. Select a card to expand it and see the details.

   

These steps were written for Windows 11 25H2 and 26H2, Windows 10 22H2. The full page with the other versions and what each result means: How to scan for malware with Microsoft Defender

Save your work first: the offline scan restarts the PC. After it finds and removes something, run Fix 1 again, because removing malware does not put back a damaged system file.

Fix 3. Check the disk with CHKDSK when DISM or SFC cannot repair

30 minutes to 2 hoursLow riskSFC says it was unable to fix some files, DISM stops with an error such as 4448, or files break again after a repair.

DISM error 4448 says a compressed Windows file has a damaged resource table. Bad sectors or file system errors can cause that, and SFC cannot fix a file that the disk keeps damaging. CHKDSK repairs the file system first.

1. Open Command Prompt as administrator. Type cmd in the search box on the taskbar, right-click Command Prompt and select Run as administrator. Select Yes when Windows asks for permission.
2. Scan the drive without changing anything. Type the command below and press Enter. Replace C: with another drive letter to check that drive. This scan only reports; it does not fix anything.

   chkdsk C:

   

3. If errors were found, run the repair. Run chkdsk with /f to fix file system errors. On the Windows drive (C:) chkdsk cannot lock the drive while Windows is running, so it offers to check it at the next restart.

   chkdsk C: /f

   

4. Schedule the check and restart. Type Y and press Enter, then restart the PC. chkdsk runs before Windows starts. Do not turn the PC off while it runs.
5. Read the result after the restart. The report of a check made at startup is not shown on the desktop. Open PowerShell and run the command below to see it, or open Event Viewer (eventvwr.msc) > Windows Logs > Application and filter by the sources Chkdsk and Wininit.

   Get-WinEvent -FilterHashtable @{LogName='Application'} | Where-Object { $_.ProviderName -match 'wininit' } | Select-Object -First 1 | Format-List TimeCreated, Message

These steps were written for Windows 11 and Windows 10 (the steps are the same). The full page with the other versions and what each result means: Check a disk for errors (chkdsk)

When CHKDSK has finished, run Fix 1 again. If DISM now completes, SFC can usually repair secur32.dll.

Fix 4. Undo a recent change with System Restore

20 to 40 minutesLow riskThe window started right after a driver, app or Windows update, and a restore point from before exists.

System Restore puts back system files, drivers and settings from a restore point. If a change left a damaged secur32.dll behind, the copy from the restore point predates it.

1. Open System Restore. Press Windows+R, type the command below and press Enter. You can also open Control Panel > Recovery > Open System Restore. If a first page opens, select Next.

   rstrui.exe

2. Choose a restore point. Select a restore point from a time before the problem started. The Description often names the event, such as a driver or app install. If the one you need is missing, select Show more restore points (shown only when there are more).

   

3. See what will change. Select Scan for affected programs. The upper list shows programs and drivers that will be removed; the lower list shows those that might come back and may need to be reinstalled. Select Close.

   

4. Start the restore. Select Next, check the summary and select Finish. Windows restarts and applies the restore point. Do not turn the PC off.
5. Check the result. After sign-in Windows reports whether the restore succeeded. Check whether the problem is gone.

These steps were written for Windows 11 and Windows 10 (the steps are the same). The full page with the other versions and what each result means: Undo recent changes with System Restore

Your documents and photos stay. Programs and drivers installed after the restore point are removed, so check them first with Scan for affected programs. If the desktop does not load, start System Restore from the recovery screen in Fix 7.

Fix 5. Reinstall the program that keeps its own secur32.dll copy

15 to 30 minutesLow riskThe path in the window is not C:\Windows\system32 but a program's own folder, and only that program shows the error.

A program that loads a secur32.dll from its own folder gets that copy instead of the Windows one. Reinstalling the current version from its maker replaces or removes the bad copy.

1. Note the full path and the program name in the window title, then select OK.
2. Scan that folder with Fix 2 first if you did not put the file there.
3. Uninstall the program from Settings > Apps > Installed apps (Windows 11) or Settings > Apps > Apps & features (Windows 10).
4. Restart the PC.
5. Install the current version from the maker's own website and open it.

Step by step, with screenshots: Uninstall a program or app in Windows. Do not delete or replace secur32.dll in C:\Windows\System32 by hand; that copy belongs to Windows.

Fix 6. Reinstall Windows and keep your files and apps

1 to 2 hoursRead the warningSFC cannot repair secur32.dll, DISM fails even after CHKDSK, or the window survives every fix above.

A repair install replaces every Windows file, secur32.dll and the component store included, with a fresh copy of your version. This is what the Microsoft Q&A moderator advised for the DISM error 4448 case.

1. Open Recovery in Settings. Open Settings > System > Recovery. Next to Fix problems using Windows Update, select Reinstall now. This keeps your apps, files and settings.

   

2. Start the reinstall. Choose whether the PC may restart on its own 15 minutes after the installation, then select OK.
3. Wait and restart. Windows Update downloads and installs a repair copy of your current Windows version. Keep the PC plugged in and online, and restart it when asked.
4. If that did not help: Reset PC. Back in Settings > System > Recovery, next to Reset this PC, select Reset PC. This keeps your personal files but removes installed apps and settings.
5. Choose Keep my files. Select Keep my files. Do not select Remove everything.

   

6. Choose where Windows comes from. Select Cloud download to download a fresh copy of Windows, or Local reinstall to use the files already on the PC (faster, but may not include the latest updates).
7. Reset. Review the summary and select Reset. The PC restarts several times.

These steps were written for Windows 11 22H2 and later. The full page with the other versions and what each result means: Reinstall Windows without losing files

Use an ISO of the same Windows edition, language and version you have. The moderator warned that if the keep options are greyed out, the ISO is wrong: cancel the setup instead of continuing.

Fix 7. Reach Safe Mode or the recovery screen when the desktop does not load

10 to 30 minutesLow riskAfter you type your password you get only a black screen and the explorer.exe - Bad Image window.

explorer.exe draws the desktop and taskbar. When it cannot load secur32.dll, there is no desktop to run repairs from. Safe Mode or the Windows recovery environment gives you a way to run Fix 1 or Fix 4.

1. Try Safe Mode first: Start Windows or a Mac in Safe Mode
2. If Safe Mode shows a desktop, run Fix 1 from there.
3. If Safe Mode shows the same black screen, as one Windows 7 reader reported, open the recovery screen instead.
4. On the recovery screen, choose Troubleshoot > Advanced options > System Restore (Fix 4).
5. If no restore point exists, try Startup Repair from the same menu: Run Startup Repair

If the secur32.dll error is still there

Stop changing things and collect what support needs. Three facts decide the next step: the exact window text, the program in the title and what SFC and DISM reported.

1. Photograph the window with the title, the path and any Error status code visible.
2. Run winver and note the version and OS build.
3. Open C:\Windows\Logs\CBS\CBS.log and look for lines that mention secur32.dll: they say whether SFC replaced the file or could not.
4. Open C:\Windows\Logs\DISM\dism.log and note the last error code, such as 4448.
5. Ask on Microsoft Q&A with the photo, the build and the log lines.

• When it is hardware. If CHKDSK finds bad sectors, or files break again after a repair install, the disk or memory is likely failing. Back up first, then test the memory with How to test your RAM with Windows Memory Diagnostic and plan to replace the disk.
• Last resort. When even a repair install fails, a clean install of Windows is the remaining software fix. It removes apps and settings, so back up your files first.

How to keep the secur32.dll error from coming back

• Never replace system files by hand. A DLL from a download site is the shortest road to the next Bad Image window.
• Shut down properly. A power cut or a forced shutdown during an update is one way system files get damaged.
• Keep restore points on. They make Fix 4 possible after a bad driver or update.
• Keep Microsoft Defender or another real-time scanner on. Malware is one of the causes of a damaged secur32.dll.
• Watch the disk. If CHKDSK finds errors more than once, back up and replace the drive before Windows files break again.

If you run Windows 10, plan the move to Windows 11 or an extended security option: Windows 10 left support on 14 October 2025 and no longer gets regular fixes.

Frequently asked questions

What is secur32.dll?

secur32.dll is a Windows system file in C:\Windows\System32. Microsoft's documentation lists it as the DLL for the Security Support Provider Interface (SSPI), the set of functions programs use to get sign-in credentials and set up authenticated, secure connections. AcquireCredentialsHandle is one of them. File Explorer and many apps load it, which is why one damaged copy can break several programs at once. It is part of Windows, not of any app that names it in an error window.

Is secur32.dll a virus?

No. The genuine secur32.dll is a signed Windows file in C:\Windows\System32. Malware can damage or replace it, though: a Microsoft Community volunteer named the trojan Bladabindi as one that can corrupt it. If the window names a secur32.dll outside System32, such as in Downloads, Temp or an app folder, or the PC behaves oddly, run a Microsoft Defender Offline scan (Fix 2), then repair Windows files with Fix 1.

Is it safe to download secur32.dll from a DLL website?

No. secur32.dll is a Windows file, so the right copy depends on your exact Windows build and comes only from Windows itself. A file from a download site, or one copied from another PC, can be the wrong version, unsigned or infected. It can also hide the real problem, a damaged component store or a failing disk. Run DISM and SFC (Fix 1) instead; they put back the correct copy for free.

Why do I get a black screen with the secur32.dll error after typing my password?

The window then comes from explorer.exe, the program that draws the desktop and taskbar. When it cannot load secur32.dll, Windows signs you in but has no desktop to show. Start in Safe Mode and run DISM and SFC from there. If Safe Mode shows the same black screen, use System Restore or Startup Repair from the recovery screen (Fix 7).

What if SFC says it was unable to fix some files?

Then the component store SFC repairs from is damaged too. Run DISM /Online /Cleanup-Image /RestoreHealth and then SFC again. If DISM also fails, as in one Microsoft Q&A case with error 4448, check the disk with CHKDSK (Fix 3) and try once more. If it still fails, a repair install (Fix 6) replaces the component store and keeps your files and apps.

What does DISM error 4448 mean with the secur32.dll error?

DISM reports it as "The WOF driver encountered a corruption in the compressed file's Resource Table". In plain words, a compressed Windows file that DISM needs is damaged, so DISM cannot rebuild the store. A reader on Windows 10 22H2 saw it together with secur32.dll Bad Image windows from many apps. The Microsoft Q&A moderator advised a repair install, which keeps apps, settings and files by default. Check the disk first (Fix 3).

Does regsvr32 fix secur32.dll?

No. Registering a DLL with regsvr32 only adds registry entries for programs that look it up that way. It does not change the content of a damaged file, and the Bad Image window is about content. For a damaged or missing secur32.dll, run DISM and SFC (Fix 1). If they cannot repair it, check the disk and then do a repair install.

Will reinstalling the app that shows the error fix secur32.dll?

Usually not. The window suggests installing the program again, but secur32.dll in C:\Windows\system32 belongs to Windows, so reinstalling an app does not touch it. A reinstall helps only when the path in the window points to the program's own folder (Fix 5). When several programs show the same window, the Windows copy is damaged and Fix 1 is the answer.

What is secur32 (что это)?

"Что это" is Russian for "what is it". secur32 is the Windows Security Support Provider Interface library, secur32.dll, which programs use to sign in and connect securely. It is a genuine Windows file in C:\Windows\System32 and should not be deleted or replaced by hand. If Windows shows an error about it, repair Windows files with DISM and SFC as described in Fix 1 of this page.