Documentation Avoid Third-Party File Extensions

# Understanding the Risks of Using Third-Party File Extensions with VeraCrypt

While VeraCrypt provides robust encryption capabilities to secure your data, using third-party file extensions for File Containers or Keyfiles could risk making the encrypted data inaccessible.
This guide provides an in-depth explanation of the associated risks, and it outlines recommendations for best practices to mitigate these risks.

## Risks Associated with File Containers

Using a third-party file extension for File Containers exposes you to several risks:

- Overwritten Metadata: Third-party applications may update their metadata, which could overwrite crucial parts of the File Container.
- Unintentional Changes: Accidentally launching a File Container with a third-party application could modify its metadata without your consent.
- Container Corruption: These actions could render the container unreadable or unusable.
- Data Loss: The data within the container might be permanently lost if the container becomes corrupted.

## Risks Associated with Keyfiles

Similar risks are associated with Keyfiles:

- Keyfile Corruption: Inadvertently modifying a Keyfile with a third-party application can make it unusable for decryption.
- Overwritten Data: Third-party applications may overwrite the portion of the Keyfile that VeraCrypt uses for decryption.
- Unintentional Changes: Accidental changes can make it impossible to mount the volume unless you have an unaltered backup of the Keyfile.

## Examples of Extensions to Avoid

Avoid using the following types of third-party file extensions:

- Media Files: Picture, audio, and video files are subject to metadata changes by their respective software.
- Archive Files: Zip files can be easily modified, which could disrupt the encrypted volume.
- Executable Files: Software updates can modify these files, making them unreliable as File Containers or Keyfiles.
- Document Files: Office and PDF files can be automatically updated by productivity software, making them risky to use.

## Recommendations

For secure usage, consider the following best practices:

- Use neutral file extensions for File Containers and Keyfiles to minimize the risk of automatic file association.
- Keep secure backups of your File Containers and Keyfiles in locations isolated from network access.
- Disable auto-open settings for the specific file extensions you use for VeraCrypt File Containers and Keyfiles.
- Always double-check file associations and be cautious when using a new device or third-party application.