Fix diagnostic.dll Errors

Sometimes Windows system displays error messages regarding corrupted or missing diagnostic.dll files. Situations like that can occur, for example, during a software installation process. Each software program requires certain resources, libraries, and source data to work properly. Corrupted or nonexistent diagnostic.dll file can therefore effect in failed execution of the started process.

diagnostic.dll file Diagnostic Module. The file was developed by for use with software. Here you will find detailed information about the file and instructions how to proceed in the event of diagnostic.dll related errors on your device. You can also download diagnostic.dll file compatible with Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Vista, Windows Vista devices which will (most probably) allow you to solve the problem.

For Windows Compatible with: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Vista, Windows Vista

File info

General information
Filename diagnostic.dll
File extension DLL
Description Diagnostic Module
Program Microsoft® Windows® Operating System
Author Microsoft Corporation
MIME type application/octet-stream
File type Dynamic link library
System Windows NT 32-bit
Copyrights © Microsoft Corporation. All rights reserved.
Character set Unicode
Language cod English (U.S.)

There are various types of errors related to diagnostic.dll file. diagnostic.dll file may be located in wrong file directory on your device, may not be present in the system, or may be infected with malicious software and therefore not work correctly. Below is a list of most common error messages related to diagnostic.dll file. If you encounter one listed below (or similar), please consider the following suggestions.

  • diagnostic.dll is corrupted
  • diagnostic.dll cannot be located
  • Runtime Error - diagnostic.dll
  • diagnostic.dll file error
  • diagnostic.dll file cannot be loaded. Module was not found
  • cannot register diagnostic.dll file:
  • diagnostic.dll file could not be loaded
  • diagnostic.dll file doesn't exist



Application could not be started because diagnostic.dll file is missing. Reinstall the application to solve the problem.


Problems related to diagnostic.dll can be addressed in various ways. Some methods are meant only for advanced users. If you don't have confidence in your skills, we suggest consulting a specialist. Fixing diagnostic.dll file errors should be approached with utmost caution for any mistakes can result in unstable or unproperly working system. If you have the necassary skills, please proceed.

diagnostic.dll file errors can be caused by various factors, so its is beneficial to try to fix them using various methods.

Step 1: Scan your computer for any malicious software

Virus Scan

Windows files are commonly attacked by malicious software that prevents them from working properly. First step in addressing problems with diagnostic.dll file or any other Windows system files should be scanning the system for malicious software using an antivirus tool.

If by any chance you don't have any antivirus software installed on your system yet, you should do it immediately. Unprotected system is not only a source of file errors, but, more importantly, makes your system vulnerable to many dangers. If you don't know which antivirus tool to choose, consult this Wikipedia article – comparison of antivirus software.

Step 2: Update your system and drivers.

Windows Update

Installing relevant Microsoft Windows patches and updates may solve your problems related to diagnostic.dll file. Use dedicated Windows tool to perform the update.

  1. Go to the Windows "Start" menu
  2. Type "Windows Update" in the search field
  3. Choose the appropriate software program (name may vary depending on your system version)
  4. Check if your system is up to date. If any unapplied updates are listed, install them immediately.
  5. After the update has been done,restart your computer in order to complete the process.

Beside updating the system, it is recommended that you install latest device drivers, as drivers can influence proper working of diagnostic.dll or other system files. In order to do so, go to your computer or device producer's website where you will find information regarding latest driver updates.

Step 3: Use System File Checker (SFC) tool

System File Checker

System File Checker is a Microsoft Windows tool. As the name suggests, the tool is used for identyfing and addressing system file related errors, including those related to diagnostic.dll file. After an error related to%fileextension% file has been discovered, the program attempts to automatically replace the diagnostic.dll file with properly working version. To use the tool:

  1. Go to the Windows "Start" menu
  2. Type "cmd" in the search field
  3. Locate "Command Prompt" result – don't run it yet:
  4. Click the right mouse button and select "Run as Administrator" option
  5. Type "sfc /scannow" in console prompt to start the program and follow the instructions

Step 4: Restoring Windows system

Windows Recovery

Another approach is to restore system to previous state, before the diagnostic.dll file error occured. In order to restore your system, follow the instructions below

  1. Go to the Windows "Start" menu
  2. Type "System Restore" in the search field
  3. Start the system restore tool – it's name may differ depending on version of the system
  4. The application will guide you through the process – read the messages carefully
  5. After the process has finished, restart your computer.

If all the above-mentioned methods failed and the diagnostic.dll file problem has not been resolved, proceed to the next step. Remember that the following steps are intended only for advanced users.

Download and replace diagnostic.dll file

The last solution is to manually download and replace diagnostic.dll file in appropriate folder on the disk. Select file version compatible with your operating system and click the "Download" button. Next, go to your web browser's "Downloaded" folder and copy the downloaded diagnostic.dll file.

Go to the folder where the file should be located and paste the downloaded file. Below is the list of diagnostic.dll file example directory paths.

  • Windows 10: C:\WINDOWS\system32\oobe\
  • Windows 8.1: C:\WINDOWS\system32\oobe\
  • Windows 8: 1: C:\WINDOWS\system32\oobe\
  • Windows 7: C:\WINDOWS\system32\oobe\
  • Windows Vista: C:\Windows\SysWOW64\oobe\
  • Windows Vista: C:\Windows\SysWOW64\oobe\

If the steps did not solve your diagnostic.dll file problem, you should consult a professional. A probability exists that the error(s) might be device-related and therefore should be resolved at the hardware level. A fresh operating system installation might be necessary – a faulty system installation process can result in data loss.

File versions list

Filename diagnostic.dll
System Windows 10
File size 141216 bytes
Date 2017-03-18
File details
MD5 21a6a68280fa3af342157ff8f7e68890
SHA1 2dec9733363881f64ad0b8d9b735e7036341d7aa
SHA256 436117f5fa53960978e05d5da9cad90b51196b40004cbce1bf763d85cdf7a794
CRC32 ba4f63e4
Example file location C:\WINDOWS\system32\oobe\
Filename diagnostic.dll
System Windows 8.1
File size 135168 bytes
Date 2014-11-21
File details
MD5 26c62a2e1f91136d1984f3d5d12f0531
SHA1 3c433224e800cb2bdc4f1e0064a49640f966afbe
SHA256 108ad6e8e6075f6e1361d22f62eff5c51574f1797f5770ae01cea49e71295d10
CRC32 b5eed3c4
Example file location C:\WINDOWS\system32\oobe\
Filename diagnostic.dll
System Windows 8
File size 130048 bytes
Date 2012-07-26
File details
MD5 6807713ccd7898c49af739e3dd4323bf
SHA1 2b310b68e350fbe7bb4ca48f67202aa3202b5f8e
SHA256 f52c71656185b2b51339f6d7a306ae7e42deccc4b0f0949b350a3f074dd1a38c
CRC32 61613651
Example file location 1: C:\WINDOWS\system32\oobe\
Filename diagnostic.dll
System Windows 7
File size 158720 bytes
Date 2009-07-14
File details
MD5 751fdfeedac5b25a22c5921a99debe5a
SHA1 ffda11f14319fb89f89e84b7f746511e9e0b7d45
SHA256 7ec91bf52059fd80e0e36ecd7c890cd3d8dd3155f3df8c7a7a50f7cf93f1f516
CRC32 d9a299f3
Example file location C:\WINDOWS\system32\oobe\
Filename diagnostic.dll
System Windows Vista
File size 121856 bytes
Date -0001-11-30
File details
MD5 33ea129441474438ae3952508ce0d420
SHA1 41b68aa11d24a1809e4d63a698c0fa9b2c371ccf
SHA256 f9ac17e0f8e32bd6aa263cd21dc6afe7c6428a227c81aae9f4f0a1f13a6737c6
CRC32 40d4855b
Example file location C:\Windows\SysWOW64\oobe\
Filename diagnostic.dll
System Windows Vista
File size 146944 bytes
Date 2008-01-21
File details
MD5 65bacb87f143aeea427e7e29bf34c420
SHA1 4fc815845c88d4c493ee9522658868d0ba366c9e
SHA256 d1531dc9446bc08574f61783a67443459753c0a934d7d5fae7b8b5666ada782f
CRC32 1767ad3c
Example file location C:\Windows\SysWOW64\oobe\