# Changing file extension warning
Choose whether to display a warning when changing a file extension.
- Tested on macOS:
- Big Sur
- Catalina
- Mojave
- Parameter type: bool
# Set to true (default value)
Display a warning when changing a file extension in the Finder
defaults write com.apple.finder "FXEnableExtensionChangeWarning" -bool "true" && killall Finder
# Set to false
Do not display the warning
defaults write com.apple.finder "FXEnableExtensionChangeWarning" -bool "false" && killall Finder
# Read current value
defaults read com.apple.finder "FXEnableExtensionChangeWarning"
# Reset to default value
defaults delete com.apple.finder "FXEnableExtensionChangeWarning" && killall Finder