Cursor Broke My App - Step by Step Fix

Five minutes ago, your app was working perfectly. Then you asked Cursor to add one small thing. Now:

• Your login doesn't work
• Pages that loaded fine are throwing errors
• Features you didn't touch are broken
• You don't even know what Cursor changed

Don't panic. Here's how to fix it.

Step 1: Stop Making It Worse (Do This First) #

STOP asking Cursor to fix it.

When Cursor breaks something, your instinct is "Cursor, fix what you just broke." This usually makes it worse because Cursor doesn't remember what it changed or why it broke.

Instead:

1. Close the Cursor chat
2. Don't make any more changes yet
3. Follow these steps

Step 2: See What Actually Changed (2 minutes) #

Check what Cursor modified:

git status

This shows every file Cursor touched.

You'll probably see way more files than you expected. You asked Cursor to change one thing, it changed seven files.

Write down which files changed. You'll need this.

Step 3: See the Exact Changes (5 minutes) #

Look at what Cursor actually did:

git diff

This shows line-by-line what changed.

Scroll through and note:

• What files have changes
• What the changes actually are
• Which changes you expected
• Which changes surprise you

The surprising changes are probably what broke things.

Step 4: Check What's Actually Broken (5 minutes) #

Try to use your app. Note exactly what doesn't work:

• Which pages crash?
• Which features fail?
• What error messages appear?
• When did it stop working? (after which change?)

Be specific. "Everything's broken" doesn't help. "Login page throws 'undefined user' error" helps.

Step 5: Decide Your Fix Strategy #

You have three options:

Option A: Undo Everything (Fastest - 1 minute) #

If you just want it working again and don't care about the feature you were adding:

git checkout .

This undoes all of Cursor's changes. Your app goes back to working state. You lose the feature you were trying to add, but app works again.

Use this if: You just want it working ASAP and can retry the feature later.

Option B: Undo Some Changes (Medium - 10 minutes) #

If you want to keep some changes but undo others:

## Keep changes to specific files
git add file1.tsx file2.tsx
 
# Undo everything else
git checkout .

Look at your git diff from Step 3. Keep the changes that make sense, undo the ones that broke things.

Use this if: Some of Cursor's changes were good, but it also broke unrelated stuff.

Option C: Fix the Breaking Changes (Slow - 30+ minutes) #

If you want to keep the feature and fix what broke:

1. Identify what broke (Step 4)
2. Look at changes to related files (Step 3)
3. Fix the breaking changes manually or ask Cursor very specifically

Use this if: You need this feature today and have time to debug.

Emergency Fix Guide (Most Common Breaks) #

Break: "Cannot read property of undefined" #

What happened: Cursor added code that assumes something exists, but it doesn't.

Quick fix:

• Find the line in error message
• Look at what's undefined
• Add a safety check:

// Cursor wrote
user.profile.name
 
// Fix it to
user?.profile?.name

Break: "Module not found" #

What happened: Cursor changed an import path or deleted a file.

Quick fix:

• Check the import statement in error
• Make sure the file it's importing actually exists
• Fix the path if wrong

Break: "Function is not defined" #

What happened: Cursor tried to call a function that doesn't exist or isn't imported.

Quick fix:

• Find where function is supposed to be
• Make sure it's imported at top of file
• Or comment out the call if not needed

Break: Database/API errors #

What happened: Cursor changed how you're calling your database or API.

Quick fix:

• Check the database/API call
• Compare to working calls in other files
• Make it match the working pattern

Break: Styling completely wrong #

What happened: Cursor modified your CSS/Tailwind classes.

Quick fix:

# Just undo styling changes
git checkout -- styles.css
# Or specific component
git checkout -- ComponentName.tsx

Step 6: Test Everything (10 minutes) #

After your fix:

1. Test the thing that broke
2. Test related features
3. Test the feature you were trying to add
4. Click around your app

Make sure everything actually works before moving on.

Step 7: Commit Your Working State #

Once it's working again:

git add .
git commit -m "Fixed Cursor breaking changes"

This gives you a safe point to return to if things break again.

How to Prevent This From Happening Again #

Why Cursor breaks things:

Cursor makes changes without seeing your full project. It modifies File A not realizing it breaks File B that depends on it.

The solution:

Give Cursor a complete view of your project so it knows what connects to what before making changes.

Two approaches:

Manual: Document your project structure so Cursor understands what connects

Automated: Use Giga to automatically track your project for Cursor

Advanced Recovery Options #

If Git Doesn't Help #

Not using git? Or committed the broken changes?

Option 1: Use Cursor to undo its changes

List every change you just made in the last 5 minutes.
Then undo all of them.

Be very specific about what to undo.

Option 2: Restore from backup

If you have Time Machine (Mac) or Windows Backup:

• Restore your project folder from before the break
• You'll lose recent work, but app will work

Option 3: Rebuild from memory

If you remember what worked:

• Manually revert the changes you identified
• Use file history in your editor
• Check browser/app logs for clues

If Multiple Things Are Broken #

Work backwards:

1. Fix the most critical break first (login, database connection)
2. Then fix secondary breaks (specific features)
3. Then fix minor breaks (styling, UI issues)

Don't try to fix everything at once. One break at a time.

If You Don't Know What Broke #

Bisect your changes:

1. Undo all changes
2. Re-apply changes one file at a time
3. Test after each file
4. When it breaks, you found the problem file

Time-consuming but guaranteed to work.

When to Start Over #

Sometimes it's faster to start over than fix:

Start over if:

• You can't figure out what broke
• Git history is too messy
• Breaks keep appearing
• You spent 2+ hours debugging
• You have a recent backup

How to start over:

1. Save your current broken state (just in case)
2. Go back to last known working commit
3. Try adding the feature again, more carefully
4. Test after each change

What to Tell Cursor Next Time #

To reduce breaks:

Instead of:

Add a delete button to the user profile

Say:

Add a delete button to UserProfile.tsx that:
1. Calls the existing deleteUser() function
2. Shows confirmation modal (like we do in Settings)
3. Only modifies UserProfile.tsx, don't touch auth or database files

Be explicit about:

• Which files to modify
• Which files to NOT touch
• What existing functions to use
• What patterns to follow

Common Questions #

Why does Cursor break things so often? #

Your project got complex. Cursor can't see how everything connects anymore. It makes changes blindly, which causes breaks.

Solution: Help Cursor understand your project

Should I stop using Cursor? #

No. The problem isn't Cursor - it's that Cursor needs help tracking complex projects. All AI tools have this limitation.

Will this keep happening? #

Yes, until you either:

• Write very detailed prompts every time (exhausting)
• Or give Cursor permanent project memory (easy)

How much time do breaks cost? #

Average: 30-60 minutes per break. If it happens twice a week, that's 2-4 hours wasted weekly.

Preventing breaks saves massive time.

Does Giga prevent all breaks? #

Not 100%, but it dramatically reduces them. Cursor sees what connects, so it makes safer changes.

Most users report breaks going from "multiple times per week" to "rarely."

What to Do Right Now #

If your app is currently broken:

1. Follow Steps 1-7 above
2. Get it working again
3. Then set up prevention

Once it's working:

1. Commit your fix
2. Set up project context management
3. Prevent this from happening again

Stop Cursor from breaking your app → Try Giga