The Autocorrect Interference
macOS includes a system-wide spelling and grammar checking feature designed to catch typos before you send an email or save a document. A key component of this system is autocorrect, which will automatically change a word you’ve typed if it believes it is misspelled. While helpful for standard communication, this feature can be incredibly frustrating if you frequently type technical jargon, non-English words, specific brand names, or code snippets. Instead of simply highlighting the unrecognized word, macOS aggressively replaces it, forcing you to constantly go back, delete the correction, and carefully re-type your original text while fighting the operating system’s assumptions.
Disabling System-Wide Autocorrect
To type exactly what you intend and stop macOS from automatically correcting your spelling, you must disable the auto-correction feature in the system settings.
Click the Apple logo in the top-left corner of your screen and select System Settings. In the left-hand sidebar, scroll down and click on Keyboard. On the right side, find the “Text Input” section and click the Edit… button next to your listed Input Sources (e.g., “U.S.”). A new panel will slide down. Look for the toggle switch labeled Correct spelling automatically. Click this switch to turn it Off (the switch will turn gray). Click Done. Your Mac will still underline misspelled words in red (if the “Check spelling” option remains active), allowing you to review them, but it will no longer forcefully change the text as you type.