Error Prevention and Recovery

Design systems that prevent errors before they happen, and when errors do occur, help people recover without shame, confusion, or lost work.

Prevention Strategies

Forgiving Input

• Accept multiple date formats ("15/03/2026", "15 March 2026", "March 15, 2026")
• Accept multiple phone formats ("(555) 123-4567", "555-123-4567", "5551234567")
• Auto-format as the user types
• Case-insensitive matching
• Trim whitespace automatically
• Show format examples next to fields ("e.g., 15/03/2026")

Smart Defaults

• Pre-select the most common option
• Pre-fill known information (name from account, address from postcode)
• Show the recommended choice for complex decisions
• Default to the safest option for irreversible settings

Progressive Validation

• Validate each field when the user moves to the next (on blur)
• Show success states for correctly completed fields
• Never validate while the user is still typing
• Never clear user input on error — always preserve their work

Minimal Demands

• Only ask for information you strictly need
• Mark optional fields, not required ones (most fields should be required by design — if they aren't needed, remove them)
• Break long forms into steps with clear progress

Error Message Design

Every error message must answer three questions:

1. What happened? (specific, not generic)
2. Why? (in plain language)
3. What do I do now? (a clear, single action)

Examples

Bad: "Invalid input" Good: "Please enter a date in the format DD/MM/YYYY — for example, 15/03/2026"

Bad: "Error 403" Good: "You don't have permission to view this page. Contact your team admin to request access."

Bad: "Password does not meet requirements" Good: "Your password needs at least 8 characters and one number. You have 6 characters."

Error Message Tone

• Never blame the user ("You entered an invalid email")
• State the situation neutrally ("We need a valid email to continue")
• Be specific about what needs to change
• Offer an alternative path when possible

Recovery Design

• Undo available for at least 10 seconds after any action
• Confirmation before destructive actions with useful detail: "Delete 'Project Alpha'? This removes all 23 files. This cannot be undone."
• Preview before submission for any consequential action
• Save progress automatically in long flows
• Alternative path when primary path fails: "Can't upload a photo? You can describe what you see instead."