isapi.dll - Analyze and How to Fix Errors

⚠️ Important Notice: Explore isapi.dll functions, usage, and compatibility for IIS servers. Essential for web developers and administrators. Manually replacing system libraries can brick future Windows updates or cause critical system failures.

Architecture:	64-bit (x64)	Compatible with only 64-bit Windows
Creation date	14.07.2009 03:29:18
File version	7.5.7600.16385
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	117.5 kb.	120320 bytes.

Hashes:

MD5: 80f68083d5356eac9f9cf71f1cb0982b ✅
SHA-1: 78ff8b733eb8091719a1a0fd37f3cc7b88320da7
SHA-256: 746ba0a619822494bc19e1e5c55a28d07e9432d05ae03da1638379b6c2fd4f49
SHA-512: 8c27dbe9d96ed96d1a47a7484a79afe2536642c6570d6a34943418fc30e77b2ecf05411e100722f687b58ae8d061ee484db290409fddfd7723cd44aeb95e811e

✅ This file is compatible with 64-bit Windows and ❌ will not work on a 32-bit operating system.

File Description: isapi.dll

The isapi.dll file is a core dynamic link library associated with Microsoft Internet Information Services (IIS). It stands for Internet Server Application Programming Interface. It allows web developers to extend the capabilities of the IIS web server using custom C/C++ scripts or programs.

Standard File Location

You will typically find this file in one of the following directories, depending on your Windows architecture and IIS installation:

• C:\Windows\System32\inetsrv\
• C:\Windows\SysWOW64\inetsrv\ (for 32-bit applications on a 64-bit Windows system)

---

How to Fix isapi.dll Errors Without Downloading

Do not download this file from third-party DLL sites, as they often contain malware. Use these built-in Windows tools to fix the issue instead:

1. Run the System File Checker (SFC)

This built-in tool scans your system for corrupted or missing Windows files and replaces them automatically.

1. Open the Start Menu.
2. Type cmd.
3. Right-click Command Prompt and select Run as administrator.
4. Type sfc /scannow and press Enter.
5. Wait for the scan to finish and restart your PC.

2. Run the DISM Tool

If SFC cannot fix the file, the Deployment Image Servicing and Management (DISM) tool will repair the Windows system image using Windows Update.

1. Open Command Prompt as administrator.
2. Type DISM /Online /Cleanup-Image /RestoreHealth and press Enter.
3. Let the process reach 100% and restart your computer.

3. Re-enable or Repair Internet Information Services (IIS)

If the error occurs while hosting web apps, the IIS feature itself might be corrupted.

1. Press Windows Key + R, type optionalfeatures, and press Enter.
2. Uncheck Internet Information Services in the list.
3. Click OK and restart your computer to remove it.
4. Open the window again, check Internet Information Services, and click OK to reinstall clean copies of the files.

4. Perform a System Restore

If the error started happening recently, you can roll Windows back to a time when it worked perfectly.

1. Open the Start Menu, type Create a restore point, and click the top result.
2. Click the System Restore button.
3. Choose a date before the error started appearing.
4. Follow the on-screen prompts and let Windows restart.

---

📊 Diagnostics Tool: Verify Your isapi.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:
msvcrt.dll
├── ntdll.dll
├── KERNEL32.dll
├── ADVAPI32.dll
├── IISUTIL.dll
└── Secur32.dll
Other versions:
️ isapi.dll 7.5.7601.26760 32-bit (x86) | ️ isapi.dll other
Similar files:
️ndisapi.dll | ️udhisapi.dll | ️aspnet_isapi.dll