“This application failed to start because adsmsext.dll was not found. Re-installing the application may fix this problem.”
You may also see “The program can’t start because adsmsext.dll is missing from your computer,” “Error loading adsmsext.dll,” or “Cannot find adsmsext.dll.” These messages mean that Windows or an application could not load adsmsext.dll, a genuine Microsoft Windows component.
The safest repair is not downloading a replacement DLL. Start with Windows Update, then repair the Windows component store with DISM and restore protected files with SFC. If only one older application reports the error, repair or reinstall that application after checking for a 32-bit or 64-bit mismatch.
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- Several programs report the error, or Windows recently failed to update: repair Windows with Windows Update, DISM, and SFC.
- Only one application or game fails: repair or reinstall that program. Its installation may be damaged or incorrectly packaged.
- The problem started after antivirus cleanup: check Windows Security Protection history before restoring anything.
- The error appears only in an older 32-bit program: investigate architecture compatibility. Do not copy a 32-bit DLL over a 64-bit Windows file.
- The message says “The specified module could not be found”: a dependency may be missing even if
adsmsext.dllis present. - The error began after a Windows upgrade, system-image restore, or malware cleanup: use Windows repair tools, System Restore, or a repair reinstall.
- You were advised to run
regsvr32 adsmsext.dll: do not make that your first repair. This is not a generic DLL registration fix.
What adsmsext.dll is
adsmsext.dll is named ADs LDAP Provider DLL. It belongs to Microsoft Windows and is part of the ADSI LDAP provider. ADSI, or Active Directory Service Interfaces, gives Windows software a way to work with directory services that use LDAP.
Microsoft documents adsmsext.dll alongside the related provider files adsldp.dll and adsldpc.dll in its ADSI system provider documentation.
Most people never open or use this file directly. An application that communicates with an LDAP directory, Active Directory environment, or another Windows directory service may call it indirectly. That is why the error can appear when starting an application even though the application itself did not install the file.
This is not a Visual C++ runtime, DirectX component, ordinary device-driver DLL, or general-purpose game dependency. Microsoft supplies it as part of Windows servicing. Microsoft security-update documentation also lists the file among Windows operating-system files, as shown in the MS16-101 file tables.
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Where should adsmsext.dll be located
On 64-bit Windows, native 64-bit system files normally reside in:
%windir%System32
The 32-bit system-file location is normally:
%windir%SysWOW64
The names can be confusing. On 64-bit Windows, System32 normally contains 64-bit system files, while SysWOW64 contains 32-bit equivalents used by 32-bit applications. Microsoft explains this redirection in its File System Redirector documentation.
Do not assume that every Windows edition has identical file paths, versions, or architecture-specific copies. Do not copy a DLL from one computer into another merely because the filenames match. Windows may have to restore a particular build from its component store.
To check the normal locations:
- Press Windows key + R.
- Enter
%windir%System32. - Press Enter.
- Search for
adsmsext.dll. - If you are using 64-bit Windows and the failing application is 32-bit, also inspect
%windir%SysWOW64.
Finding the file does not prove that it is healthy. A dependency may be missing, the file may be damaged, or the application may be requesting the wrong architecture.
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Because adsmsext.dll is a Windows component, begin with Windows Update.
Windows 11
- Open Start.
- Select Settings.
- Select Windows Update.
- Choose Check for updates.
- Install all available updates.
- Restart the computer, even if Windows does not immediately require it.
- Open the affected application again.
Windows 10
- Open Start.
- Select Settings.
- Open Update & Security.
- Select Windows Update.
- Choose Check for updates.
- Install pending updates.
- Restart Windows and test the program.
This can replace a missing system component or complete a servicing operation that was interrupted. If Windows Update reports an error, restart once and check again before moving to DISM.
If the error began immediately after an update, Windows recovery options may also allow you to uninstall the recent update or use System Restore. Microsoft lists those choices in its Windows recovery options.
Fix 2: Repair Windows with DISM and SFC
This is the main repair for a deleted, corrupted, or mismatched Windows copy of adsmsext.dll. DISM repairs the Windows component store. SFC then checks protected system files and replaces incorrect versions.
Run DISM
- Open Start.
- Type
Command Prompt. - Right-click Command Prompt.
- Select Run as administrator.
- Approve the User Account Control prompt.
- Enter this command:
DISM.exe /Online /Cleanup-Image /RestoreHealth
- Press Enter.
- Wait for the operation to finish.
- Restart Windows if DISM requests it.
Do not close the window just because the percentage appears to pause. DISM can take time while it checks and repairs the component store. Microsoft documents this command in its guide to repairing a Windows image.
Run SFC after DISM
After DISM completes:
- Open an elevated Command Prompt again if necessary.
- Enter:
sfc /scannow
- Press Enter.
- Wait until verification reaches 100 percent.
- Restart the computer.
- Test the application that showed the error.
Microsoft describes SFC in its System File Checker documentation.
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A successful result may say that Windows Resource Protection found no integrity violations, or that it found corrupt files and repaired them. If SFC says it found corruption that it could not repair, run DISM first if you skipped it, then run sfc /scannow again.
If you need deeper evidence, Windows records servicing details in:
%windir%LogsCBSCBS.log
Do not manually replace adsmsext.dll while Windows repair is still available. Manual replacement can introduce the wrong architecture or version and can hide the underlying component-store problem.
If repeatedly hunting through Windows repair commands is becoming guesswork, Outbyte PC Repair can scan for system problems and show what it identifies; its free scan shows the issues, while repair is performed by the full version. It is optional, and DISM/SFC remain the appropriate Microsoft repair path.
Fix 3: Use Windows 11’s repair reinstall
If Windows Update, DISM, and SFC do not resolve the problem, Windows 11 may offer a repair reinstall that keeps your applications, files, and settings.
- Open Settings.
- Select System.
- Select Recovery.
- Find Fix problems using Windows Update.
- Select Reinstall now.
- Follow the on-screen instructions.
- Keep the computer connected to power and connected to the internet during the process.
This reinstalls the current Windows version without treating adsmsext.dll as an independently downloadable file. Availability depends on the Windows configuration and update state. Microsoft explains the feature in its guide to reinstalling the current version of Windows.
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Fix 4: Repair or reinstall the affected application
If only one program reports adsmsext.dll, Windows may be healthy and the application may be the real problem. This is especially possible after an incomplete uninstall, an interrupted update, an old system-image restore, or a program that was packaged with an incorrect dependency expectation.
First use the application’s own repair option:
- Open Settings.
- Select Apps.
- Select Installed apps.
- Find the affected application.
- Select its three-dot menu.
- Select Advanced options.
- Choose Repair.
- Start the application again.
If Repair does not help, return to the same screen and use Reset if available. Reset can remove application data and settings, so use it only after considering what the program stores locally.
For a traditional desktop program:
- Open Control Panel.
- Select Programs.
- Select Programs and Features.
- Select the affected program.
- Choose Repair or Change, if offered.
- If no repair option exists, uninstall the program.
- Restart Windows.
- Reinstall it from the vendor’s official installer or the original trusted distribution channel.
For a game, use the launcher’s built-in verify, repair, or verify files function where available. Do not download adsmsext.dll into the game directory. A copied file may mask the problem temporarily while creating a version or architecture conflict.
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Fix 5: Check 32-bit and 64-bit compatibility
A 32-bit process cannot load a 64-bit DLL, and a 64-bit process cannot load a 32-bit DLL. Microsoft explains these restrictions in its guide to running 32-bit applications.
Look for an architecture mismatch when:
- the failing program is old;
- the problem affects only one application;
- the application was copied from another computer;
- a third-party installer placed files in the application directory;
- the error appeared after switching between x86 and x64 editions of a program.
Check the application’s documentation or installer options to determine whether it is 32-bit or 64-bit. Do not overwrite the copy in System32 with one from SysWOW64, and do not copy either system copy into an application folder.
If the application is old, install its current supported release or contact its vendor. If the application is 32-bit on 64-bit Windows, that arrangement can work, but every DLL loaded by the process still needs to match the process architecture.
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Fix 6: Check whether antivirus quarantined the file
Antivirus quarantine is possible, particularly after malware cleanup or a false-positive detection. It is not proof that the file was malicious.
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In Windows Security:
- Open Start.
- Type Windows Security.
- Open the app.
- Select Virus & threat protection.
- Select Protection history.
- Open the relevant quarantined item.
- Verify that it refers to
adsmsext.dlland that the detection is a false positive before taking action. - Use Restore only when you have verified the detection.
- Run Windows Update, DISM, and SFC afterward.
Microsoft documents the process in Restore quarantined files in Microsoft Defender Antivirus.
If the detection is credible, do not restore the file. Allow Defender to remove it, run a full or offline scan, back up important data, and repair Windows through its supported servicing tools.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Fix 7: Update a driver only when the evidence points there
adsmsext.dll is not a device-driver file, so updating random drivers is not a normal fix. Consider driver troubleshooting only if the error began with a hardware change or appears alongside a device failure, Windows crash, or a clear driver-related event.
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To check Device Manager:
- Right-click Start.
- Select Device Manager.
- Expand the category related to the suspected device.
- Right-click the device.
- Select Properties.
- Review the General and Driver tabs.
- Use Update driver only when you have identified the relevant device.
- Restart Windows and test again.
Do not uninstall unrelated devices just because they show an old driver date. A driver update cannot repair a missing Windows ADSI provider.
If you are manually checking many hardware vendors and driver versions, Outbyte Driver Updater can scan for outdated drivers and identify what it finds; its free scan shows the detected issues, while installation is handled by the full version. It is optional and does not replace DISM, SFC, or application reinstallation for this Windows component.
Why regsvr32 is usually the wrong fix
regsvr32 registers DLLs that provide registration functionality, such as the DllRegisterServer entry point. Microsoft’s regsvr32 documentation describes it as a registration tool, not a universal DLL repair command.
Running this command blindly:
regsvr32 adsmsext.dll
may produce an entry-point error or another failure. That does not mean Windows needs a different copy of the file. Ordinary system-file corruption is repaired through Windows servicing, DISM, and SFC.
Use regsvr32 only when the software vendor or Microsoft specifically instructs you to register a DLL and documents that the file supports registration. Do not use it as a substitute for repairing Windows.
If the error still remains
Work through these checks in order:
- Confirm whether one application or multiple applications fail.
- Install pending Windows updates and restart.
- Run DISM, then SFC.
- Repair or reinstall the affected application.
- Check the application architecture.
- Review antivirus quarantine and run a Defender scan.
- Use System Restore if the error began after a known system change.
- Consider a Windows repair reinstall when system-wide errors continue.
- Back up important data and check disk health if corruption keeps returning.
“The specified module could not be found” can refer to a dependency of adsmsext.dll, not necessarily the named file itself. That is another reason a random DLL download is unreliable: it does not identify or repair the missing dependency.
Preventing another adsmsext.dll error
- Keep Windows Update enabled and restart after major servicing operations.
- Avoid interrupted upgrades and forced shutdowns during updates.
- Install applications from their official source.
- Keep an application’s files together rather than copying DLLs between folders.
- Do not use random DLL download sites pages.
- Do not replace files in
System32orSysWOW64manually. - Maintain current backups before system-image restoration or major upgrades.
- Investigate antivirus detections instead of restoring quarantined files automatically.
- Run DISM and SFC when Windows system-file corruption is suspected.
FAQ
Is adsmsext.dll safe?
The file is a legitimate Microsoft Windows component named ADs LDAP Provider DLL. A file with that name outside the expected Windows system locations still deserves investigation, because filenames can be copied or imitated.
Should I download adsmsext.dll from the internet?
No. Random DLL download sites sites may provide malware, the wrong Windows build, or the wrong architecture. They also do not repair the component store or a missing dependency. Use Windows Update, DISM, SFC, Windows recovery, or the affected application’s official installer.
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Not usually. adsmsext.dll is an ADSI LDAP provider supplied by Windows, not a Visual C++ runtime. Repair Windows first, then repair the specific application if only that program fails.
Does adsmsext.dll need to be registered?
Do not assume so. regsvr32 is for DLLs that expose registration functionality, and it is not a general repair command. Use DISM and SFC for a damaged Windows component.
Why does the message say a module is missing when the file exists?
The application may be missing a dependency, may be loading the wrong architecture, or may be unable to use a damaged copy. Finding the filename in System32 does not rule out those causes.
Can I copy the file from another PC?
That is unsafe. Windows builds and architectures differ, and the copied file may conflict with the component store. Let Windows restore the correct file through servicing and repair tools instead.
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