To register a DLL in Windows 10, open Command Prompt as an administrator, type regsvr32 "C:\path\to\file.dll" using the DLL’s full path, and press Enter. A message says DllRegisterServer succeeded. To unregister it, add /u.
Applies to: Windows 10. Checked against Microsoft Learn on September 27, 2026.
Before you start
Only register a DLL when an app’s instructions or support team tell you to. Most apps register their own files when you install them. If an app says a DLL is missing, reinstalling the app usually fixes it better than registering the file yourself. Never download DLL files from DLL download sites.
Register a DLL
- Select Start, type cmd, right-click Command Prompt, and select Run as administrator.
- Type this, using your DLL’s full path in quotation marks:
regsvr32 "C:\Program Files\Contoso\Tools\contoso.dll"
- Press Enter.
- Select OK on the message that says it succeeded.
To copy a file’s full path, hold Shift, right-click it, and select Copy as path.
32-bit DLLs on 64-bit Windows
On 64-bit Windows 10, use the 32-bit version of regsvr32 for a 32-bit DLL:
C:\Windows\SysWOW64\regsvr32.exe "C:\path\to\file.dll"
If you use the wrong one, you may see an error that the module couldn’t be loaded.
Unregister a DLL
Run:
regsvr32 /u "C:\path\to\file.dll"
If you see an error
- The module was loaded but the entry-point DllRegisterServer was not found: this DLL can’t be registered. That’s normal for many DLLs. Reinstall the app instead.
- The module failed to load: check the path, and try the 32-bit regsvr32 above.
- Access denied or 0x80070005: run Command Prompt as an administrator.
- Windows system DLL errors: run an SFC scan instead. See how to run an SFC scan in Windows 10.
Frequently asked questions
How do I open Command Prompt as an administrator?
See how to run a program as administrator in Windows 10 or how to open Command Prompt in Windows 10.
Do I need to restart after registering a DLL?
Usually not. Restart the app that uses it.
Microsoft’s reference is regsvr32. More help is on our Windows Help & Guides page.
Matt Jacobs has been working as an IT consultant for small businesses since receiving his Master’s degree in 2003. While he still does some consulting work, his primary focus now is on creating technology support content for SupportYourTech.com.
His work can be found on many websites and focuses on topics such as Microsoft Office, Apple devices, Android devices, Photoshop, and more.