amsi.dll - Analyze and How to Fix Errors

★★★★☆ Verified File (27.08.2026)

⚠️ Important Notice: AMSINTOOLS library component for enhanced application security measures. Manually replacing system libraries can brick future Windows updates or cause critical system failures.

Architecture:	other	️ Not detected
Antivirus scan	✅ Clean	No viruses detected.
Digital signature	🟡 Not signed	Signature missing. The file may have been modified.
Hash Integrity	ℹ️ Unverified	File Hash protection is missing.
File size	16.3 kb.	16677 bytes.

Hashes:

MD5: 247cd35421b6f380e09732211fffd495
SHA-1: 7710e6541a90bf93329b174a5d8f59f129f5b0f8
SHA-256: 9077a0e7f4bbdd665c316ca833e65df89aae6ac2168679e3eef4adb6de8fb549
SHA-512: 194b1e29e02d15625f3b925037d6af867ab332029375c999aa9fbc3be251dbab3f0c47cc259fcfeca5d0f26d939484c67a3d64e3188222a0b735d355308fd6a0

What is amsi.dll?

Amsi.dll is the core component of the Antimalware Scan Interface (AMSI), a critical Windows security feature introduced by Microsoft. It acts as an interface that allows applications (like PowerShell, Command Prompt, or third-party apps) to send script content and code to the installed antivirus program for scanning before execution.

Standard File Location

The legitimate amsi.dll file is a system file and is located in the following standard directories:

64-bit systems (64-bit version): C:\Windows\System32\amsi.dll
64-bit systems (32-bit compatibility version): C:\Windows\SysWOW64\amsi.dll

If you find this file inside a user folder, desktop, or temporary directory, it might be malware masking itself as a system file.

How to Fix amsi.dll Errors Without Downloading Anything

Errors related to amsi.dll usually mean the file is corrupted, missing, or blocked by a conflicting program. Do not download dll files from third-party websites, as they often contain malware.

Here are the safest ways to fix the error using built-in Windows tools:

Method 1: Run System File Checker (SFC) and DISM

Windows has built-in repair tools that can automatically replace corrupted system files like amsi.dll using safe, internal backups.

Press the Windows Key, type cmd, right-click Command Prompt, and select Run as administrator.
Type the following command to check and repair system files, then press Enter:
```
sfc /scannify
```
After the scan finishes, type this command to repair the Windows system image, then press Enter:
```
DISM /Online /Cleanup-Image /RestoreHealth
```
Restart your computer.

Method 2: Re-register the DLL File

If the file exists but Windows is having trouble recognizing it, you can manually re-register it.

Open Command Prompt as an administrator.
Type the following command and press Enter:
```
regsvr32 amsi.dll
```
If you get a success message, click OK and restart your app.

Method 3: Check for Windows Updates

Microsoft frequently updates system files like amsi.dll to fix bugs and vulnerabilities.

Press Windows Key + I to open Settings.
Go to Update & Security (or Windows Update on Windows 11).
Click Check for updates and install any available updates.
Restart your PC.

Method 4: Update or Disable Third-Party Antivirus

Sometimes, third-party antivirus software conflicts with the Windows AMSI module, leading to crashes or errors.

Temporarily disable your third-party antivirus (e.g., Avast, Kaspersky, McAfee).
Check if the error persists.
If the error goes away, update your antivirus to the latest version, or uninstall it and rely on the built-in Windows Defender.

If you'd like, let me know:

What is the exact error message you see on your screen?
When does the error happen? (e.g., when launching a specific app, opening PowerShell, or booting up Windows?)
Which version of Windows are you currently using?

I can help you narrow down the exact cause and fix it.

📊 Diagnostics Tool: Verify Your `amsi.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.

Other versions:
️ amsi.dll 10.0.19041.4355 32-bit (x86) | ️ amsi.dll 10.0.19041.4355 64-bit (x64)
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