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Quick Fixes

Excel Keeps Crashing - Here's How to Fix It

Excel crashing mid-spreadsheet is painful. Doubly so when you forgot to save.

Before you blame Microsoft (fair), try these fixes. Most Excel crashes have simple causes.

1. First: Turn on AutoSave

Before we fix anything - stop this from hurting you again.

If you have Microsoft 365:

  • Save the file to OneDrive or SharePoint
  • AutoSave toggle appears in top-left
  • Turn it On

If you don't:

  • File → Options → Save
  • Set "Save AutoRecover info every" to 1 minute

Now let's fix the crashing.

2. Check if it's one specific file

Does Excel crash with every file or just one?

Just one file: The file is corrupted or too complex. See fixes #5 and #6.

Every file: Excel itself has a problem. See fixes #3 and #4.

3. Start Excel in Safe Mode

This opens Excel without add-ins - the most common crash cause.

How:

  1. Hold Ctrl key
  2. Click Excel icon
  3. Click "Yes" when asked about Safe Mode

If Excel works fine in Safe Mode: An add-in is the problem. Go to fix #4.

Still crashes in Safe Mode: Excel installation is broken. Skip to fix #7.

4. Disable dodgy add-ins

Add-ins are the #1 cause of Excel crashes. That PDF converter or data tool you installed? Probably the culprit.

Disable them:

  1. File → Options → Add-ins
  2. At bottom: Manage → COM Add-ins → Go
  3. Uncheck everything → OK
  4. Restart Excel

Works now? Re-enable add-ins one by one to find the bad one.

Common troublemakers: Adobe PDF maker, old data connectors, antivirus plugins.

5. Your file is too big

Excel struggles with:

  • Files over 20MB
  • More than 100,000 rows
  • Hundreds of formulas referencing each other
  • Loads of conditional formatting

Check file size: Right-click file → Properties

If it's massive:

  • Delete unused sheets
  • Remove old data you don't need
  • Copy-paste values instead of formulas (Paste Special → Values)
  • Clear conditional formatting on large ranges

6. Conditional formatting has gone mad

This is a sneaky one. Conditional formatting can accumulate invisibly and slow everything down.

Check it:

  1. Select all (Ctrl + A)
  2. Home → Conditional Formatting → Manage Rules
  3. Show rules for: This Worksheet

See hundreds or thousands of rules? Clear them:

  • Conditional Formatting → Clear Rules → Clear Rules from Entire Sheet

Then re-apply only what you actually need.

7. Repair Office

If Excel keeps crashing regardless of file:

Windows:

  1. Settings → Apps → Apps & features
  2. Find "Microsoft 365" or "Microsoft Office"
  3. Click → Modify → Repair
  4. Try "Quick Repair" first
  5. If that fails, try "Online Repair"

Mac:

  • Re-download from office.com/myaccount

8. Check for updates

Outdated Excel = buggy Excel.

  1. Open Excel
  2. File → Account → Update Options → Update Now

The nuclear option

Nothing worked? The file might be corrupted beyond easy repair.

Try this:

  1. Open Excel (blank)
  2. File → Open → Browse to your file
  3. Click the little arrow on "Open" button
  4. Select "Open and Repair"

This sometimes recovers corrupted files.

Still crashing?

At this point it's either:

  • Serious file corruption needing manual recovery
  • System-level issues
  • Hardware problems (bad RAM can cause random crashes)

Need help? I fix Excel nightmares for small businesses. Get your data back, spreadsheet working, sanity restored.

Get in touch →

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https://alexsusanu.com/blog/excel-keeps-crashing/

Excel crashing in the middle of work is the worst.

Usually it's one of these culprits:

- The file got too big
- Add-ins are fighting each other
- Your Office install is corrupted
- Conditional formatting went mad

Before you lose another hour of work, here's how to fix it (and stop it happening again).

Bonus: Turn on AutoSave. Seriously.

https://alexsusanu.com/blog/excel-keeps-crashing/

Why Is My Computer So Slow? 5 Fixes That Actually Work

We've all been there. You're trying to get work done, and your computer has other plans - spinning, freezing, taking forever to open anything.

Before you throw it out the window (or spend £800 on a new one), try these fixes. They work 90% of the time.

1. Actually restart it (properly)

"But I shut the lid every night!"

That's not restarting. That's sleep mode. Your computer has been "on" for weeks, accumulating junk in memory.

Do this:

  • Windows: Start menu → Power → Restart (not Shut Down)
  • Mac: Apple menu → Restart

Yes, there's a difference between Restart and Shut Down. Restart clears more stuff out.

Do this once a week minimum.

2. Check what's hogging your startup

Half the slowness is programs loading when you turn on your computer. Spotify, Dropbox, Adobe, Zoom - they all want to start immediately.

Windows:

  1. Press Ctrl + Shift + Esc (opens Task Manager)
  2. Click "Startup" tab
  3. Right-click anything you don't need immediately → Disable

Mac:

  1. System Preferences → Users & Groups
  2. Click your name → Login Items
  3. Remove anything you don't need at startup

Safe to disable: Spotify, Adobe Creative Cloud, Microsoft Teams (if you open it manually anyway), Dropbox, OneDrive.

Don't disable: Antivirus, graphics drivers.

3. Clear out the junk

Temporary files pile up. Browser cache grows. Downloads folder becomes a graveyard.

Quick cleanup on Windows:

  1. Press Windows key + R
  2. Type cleanmgr and press Enter
  3. Select your drive, click OK
  4. Check all boxes, click OK

On Mac:

  1. Apple menu → About This Mac → Storage → Manage
  2. Use recommendations to clear space

Also: Empty your Downloads folder. Right now. You don't need that PDF from 2019.

4. Check your storage

If your hard drive is more than 90% full, your computer will crawl. It needs breathing room.

Windows: Open File Explorer → Right-click C: drive → Properties

Mac: Apple menu → About This Mac → Storage

Below 10% free? Time to delete stuff or move files to external storage/cloud.

5. Check for stuck updates

Windows especially loves to download updates in the background and get stuck halfway. This eats resources.

Windows:

  1. Settings → Update & Security → Windows Update
  2. If something's stuck, click "Retry" or "Download"
  3. Restart after updates finish

Mac:

  1. System Preferences → Software Update
  2. Install anything pending

Still slow?

If none of this helped, the problem might be:

  • Hardware dying (hard drive failing, not enough RAM)
  • Malware running in the background
  • It's genuinely old (8+ years is pushing it)

At this point you need someone to look at it properly.

Need help? I sort out slow computers remotely for small businesses. No jargon, fixed in hours not days.

Get in touch →

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Your work computer shouldn't take 10 minutes to start up.

If you're staring at a spinning wheel more than your actual work, here are 5 things that actually fix slow computers (no IT degree needed):

1. Restart it properly (not just close the lid)
2. Check what's running on startup
3. Clear out the junk
4. Check your storage space
5. Make sure updates aren't stuck

https://alexsusanu.com/blog/slow-computer-fixes/