The Developer’s Nightmare
macOS includes a system-wide text substitution feature that automatically converts straight quotation marks (” and ‘) into their typographically “correct” curly equivalents (“ ” and ‘ ’), often called smart quotes. For general prose writing, this produces a more polished visual result. However, for software developers, system administrators, and anyone who writes code, scripts, or configuration files in a plain-text editor, this automatic substitution is catastrophic. A single curly quote pasted into a terminal command, a JSON configuration file, or a Python script will cause a silent syntax error that can take hours to debug because the curly character is visually almost identical to the straight one.
Disabling System-Wide Smart Quotes
To stop macOS from automatically converting your straight quotation marks into curly smart quotes across all applications, you must disable the substitution at the operating system level.
Click the Apple Logo in the top-left corner of your screen and select System Settings. In the left-hand sidebar, click on Keyboard. Scroll down to the “Text Input” section and click on the Edit… button next to “Input Sources” (on older macOS versions, this is under System Preferences > Keyboard > Text). In the text replacement panel that appears, look for the checkbox labelled Use smart quotes and dashes. Uncheck this option. Once disabled, macOS will stop replacing straight quotes with curly variants system-wide, affecting TextEdit, Notes, Mail, Safari form fields, and any other application that hooks into the system’s text substitution engine. Individual applications like Pages or Keynote may have their own separate smart-quote settings under Edit > Substitutions > Smart Quotes; ensure you uncheck that per-app toggle as well for complete coverage.