smime3.dll - Analyze and How to Fix Errors

★★★★☆ Verified File (27.08.2026)

⚠️ Important Notice: Solve Windows security certificate issues with smime3.dll - Essential for secure email communication. Manually replacing system libraries can brick future Windows updates or cause critical system failures.

Architecture:	32-bit (x86)	Compatible with 32 and 64-bit Windows
Creation date	08.10.2025 22:43:54
File version	3.39.0.0
Antivirus scan	✅ Clean	No viruses detected.
Digital signature	🟡 Not signed	Signature missing. The file may have been modified.
Hash Integrity	✅ MD5: Verified	File Hash protection is missing.
File size	99.5 kb.	101888 bytes.

Hashes:

MD5: bf5d364ff0bd061fd6a3fab2a46695cc ✅
SHA-1: 4ca79afd5b7de17e7e9bdca84503e0ea03d01e00
SHA-256: 8425ffa89a9bc4a523e28492063298d9f0e5cb11181f7e5b65d6d05676e32a22
SHA-512: f7b3d2d2566aea71170b5b3e3f324bf96d6dbf1e9bd8d1e9ef341ae8028517ced2ec76c008dba4a6a0ce5fcfaa8783877e1b032be79d056e412504804a10626a

✅ This file is compatible with 32-bit Windows and can run on ✅ 64-bit Windows (via the WOW64 subsystem).

To fix a smime3.dll error without downloading anything, you need to repair the corrupted application, restore the file from your system, or re-register the DLL via Command Prompt. smime3.dll is an essential component of the NSS S/MIME Library used by software like Mozilla Firefox and Thunderbird. Follow these steps to resolve the issue safely using built-in Windows tools.

?? Method 1: Re-Register the DLL File

If the file exists on your PC but is not recognized by the operating system, you can manually re-register it.

Click the Start menu and type cmd.
Right-click Command Prompt and choose Run as administrator.
Type the following command and press Enter: regsvr32 smime3.dll
Restart your computer and test the application.

??? Method 2: Repair or Reinstall the Affected Software

If the error occurs when opening a specific app (e.g., Firefox), the app can fix itself using its original local files.

For Windows Apps: Open Settings > Apps > Installed apps. Find the program, click the three dots, select Advanced options, and click Repair.
For Desktop Software: Open the Control Panel, click Uninstall a program, select the application, and choose Repair or Change if available.

?? Method 3: Run the System File Checker (SFC)

Windows has an integrated scanner that searches for missing or corrupted system files and automatically replaces them with healthy cached copies.

Open Command Prompt as an administrator.
Type sfc /scannow and press Enter.
Wait for the verification to reach 100%.
Restart your computer if the tool repaired any files.

??? Method 4: Check the Recycle Bin

Sometimes, DLL errors occur because the file was accidentally deleted during a manual cleanup or by a software uninstaller.

Open your Recycle Bin on the desktop.
Search for smime3.dll in the top-right search bar.
If found, right-click the file and select Restore.

? Method 5: Use Windows System Restore

If the error started happening recently after a system modification, you can roll Windows back to a point when everything worked.

Type Create a restore point in the Windows search bar and click it.
Click the System Restore... button.
Select a date prior to when the smime3.dll error first appeared.
Follow the on-screen prompts to complete the process.

If you would like to narrow down the solution, please tell me which specific application triggers this error and what exact error message you see on your screen.

📊 Diagnostics Tool: Verify Your `smime3.dll` File

Worried that the file on your PC has been modified by malware? Drop it into the form below. Our script will verify its file size, cryptographic hash (MD5/SHA-1), and check for a valid Microsoft digital signature.

Connected files:
nss3.dll
├── nssutil3.dll
├── plc4.dll
├── plds4.dll
├── nspr4.dll
├── MSVCR90.dll
└── KERNEL32.dll
Other versions:
️ smime3.dll 3.73.1.0 64-bit (x64)