What are def.ini Error Messages?

General def.ini Runtime Errors

def.ini file errors often occur during the startup phase of Avast Internet Security, but can also occur while the program is running. These types INI errors are also known as “runtime errors” because they occur while Avast Internet Security is running. Here are some of the most common def.ini runtime errors:

• def.ini could not be found.
• def.ini error.
• def.ini failed to load.
• Error loading def.ini.
• Failed to register def.ini / Cannot register def.ini.
• Runtime Error - def.ini.
• The file def.ini is missing or corrupt.

Most INI errors are due to missing or corrupt files. Your def.ini file could be missing due to accidental deletion, uninstalled as a shared file of another program (shared with Avast Internet Security), or deleted by a malware infection. Furthermore, def.ini file corruption could be caused from a power outage when loading Avast Internet Security, system crash while loading or saving def.ini, bad sectors on your storage media (usually your primary hard drive), or malware infection. Thus, it’s critical to make sure your anti-virus is kept up-to-date and scanning regularly.

How to Fix def.ini Errors in 3 Steps (Time to complete: ~5-15 minutes)

If you're encountering one of the error messages above, follow these troubleshooting steps to resolve your def.ini issue. These troubleshooting steps are listed in the recommended order of execution.

To begin System Restore (Windows XP, Vista, 7, 8, and 10):

1. Hit the Windows Start button
2. When you see the search box, type "System Restore" and press "ENTER".
3. In the search results, find and click System Restore.
4. Please enter the administrator password (if applicable / prompted).
5. Follow the steps in the System Restore Wizard to choose a relevant restore point.
6. Restore your computer to that backup image.

If the Step 1 fails to resolve the def.ini error, please proceed to the Step 2 below.

You can uninstall Avast Internet Security software by following these instructions (Windows XP, Vista, 7, 8, and 10):

1. Hit the Windows Start button
2. In the search box, type "Uninstall" and press "ENTER".
3. In the search results, find and click "Add or Remove Programs"
4. Find the entry for Avast Internet Security 19.6.2383 and click "Uninstall"
5. Follow the prompts for uninstallation.

After the software has been fully uninstalled, restart your PC and reinstall Avast Internet Security software.

If this Step 2 fails as well, please proceed to the Step 3 below.

Avast Internet Security 19.6.2383

Avast Software

When the first two steps haven't solved your issue, it might be a good idea to run Windows Update. Many def.ini error messages that are encountered can be contributed to an outdated Windows Operating System. To run Windows Update, please follow these easy steps:

1. Hit the Windows Start button
2. In the search box, type "Update" and press "ENTER".
3. In the Windows Update dialog box, click "Check for Updates" (or similar button depending on your Windows version)
4. If updates are available for download, click "Install Updates".
5. After the update is completed, restart your PC.

If Windows Update failed to resolve the def.ini error message, please proceed to next step. Please note that this final step is recommended for advanced PC users only.

If Those Steps Fail: Download and Replace Your def.ini File (Caution: Advanced)

If none of the previous three troubleshooting steps have resolved your issue, you can try a more aggressive approach (Note: Not recommended for amateur PC users) by downloading and replacing your appropriate def.ini file version. We maintain a comprehensive database of 100% malware-free def.ini files for every applicable version of Avast Internet Security. Please follow the steps below to download and properly replace you file:

1. Locate your Windows operating system version in the list of below "Download def.ini Files".
2. Click the appropriate "Download Now" button and download your Windows file version.
3. Copy this file to the appropriate Avast Internet Security folder location:
   
   Windows 10: C:\Program Files\AVAST Software\Avast\defs\19102900\
   Windows 10: C:\Program Files (x86)\AVG\Antivirus\defs\19102202\
   Windows 10: C:\Program Files\AVAST Software\Avast\defs\19093002\
   Windows 10: C:\Program Files\AVAST Software\Avast\defs\19092903\
   Windows 10: C:\Program Files\AVG\Antivirus\defs\19093002\
   Show 1 more directory +

   Windows 10: C:\Program Files\AVG\Antivirus\defs\19092903\
   
4. Restart your computer.

If this final step has failed and you're still encountering the error, you're only remaining option is to do a clean installation of Windows 10.

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