Back to blog list

3 ways to fix "Excel cannot open the file 'filename.xlsx' because the file format or file extension is not valid" error

Excel File Not Opening? – Here's What You Need to Know
Excel won

Sometimes Excel files don't open properly or don't open at all, which can cause a lot of stress and panic. No one wants to lose important information or create another document from scratch, especially if they're dealing with a large data set. There are several reasons why an Excel workbook will refuse to open and understanding the cause is the key to fixing it.

Signs That Excel Won't Open

Sometimes the Excel program just doesn't react when you double-click on a file. Sometimes it opens but the page is either blank with empty cells or grey with no cells. The grey screen usually happens after program upgrades. If you have recently upgraded from MS 2007 to 2010, 2013, or 2016, you may experience this problem.

You may get a white screen after opening a file if you're running Microsoft Excel 2016 on Windows 10. In most of these cases, Excel won't open unless you identify the root cause and recover the document.

How to Fix the Issue?

It isn't always possible to recover a corrupted file and restore data, which is why users must always back everything up. We have some tricks that can help you recover a lost document. Here are some tips to try if Excel won't open:

1. DDE Checkbox

Ignore other applications that use Dynamic Data Exchange (DDE)

DDE stands for Dynamic Data Exchange and it is a system that allows communication between two documents. If this system is switched off and the 'Ignore other applications that use Dynamic Data Exchange (DDE)' box is checked, it can cause issues. People often face problems with opening documents because the DDE isn't functioning and there's no communication between the operating system and Excel. The simplest way to resolve the issue is to uncheck the box and here's how you can do that:

  • Open any Excel document.
  • Go to File > Options > Advanced > Locate General Section
  • Uncheck the 'Ignore other applications that use Dynamic Data Exchange (DDE)' box
  • Click on 'OK'

Try to open the document you had an issue with after completing these steps. In most cases, engaging DDE will resolve the issue and you will be able to access the data. We recommend making another copy of the file regardless to ensure there are no issues.

2. Excel File Associations

Set default file associations in windows 10 Default apps

Sometimes it isn't possible to identify the root cause of the problem so finding a specific solution isn't an option. Resetting the Excel file associations will restore Excel to its default settings, undoing any damaging alterations to the program. In most cases, that can help resolve all issues and ensure the program is running smoothly once again. Here's a look at how to restore file associations if Excel won't open:

In Windows 10:

  • In the Windows Search Box, Search for 'Default apps'.
  • Click on the 'Set defaults by app' option lower down in the list.
  • Select Excel in your Default Programs list and click the 'Manage' button.
  • Review the list of File type and protocol associations, and ensure the Excel extension of your file is properly associated.

In earlier versions of Windows:

  • Go to 'Start' and open 'Control Panel'.
  • Click on the 'Programs' option.
  • Choose the 'Default Programs' option.
  • Select the 'Set your default programs' option.
  • Select Excel in your Default Programs list.
  • Click 'Choose default for this program'.
  • The 'Set program associations' screen will appear.
  • Click 'Select All' and then click 'Ok'.

This will reset Excel and undo errors, which will hopefully give you access to the Excel document once again.

3. Repair Microsoft Office

Repair Microsoft Office

Repairing the entire office suite when Excel won't open may sound like overkill, but it can help resolve the issue.

In Windows 10:

  • In the Windows Search Box, search for 'Add or Remove Programs'
  • Scroll or search the list until you find 'Microsoft Office', the click on 'Modify'
  • A confirmation dialoge will appear that you'll need to accept to perform the repair.
  • Choose 'Quick Repair' which will fix most issues.
  • Alternatively, try 'Online Repair', which takes a little longer and requires an internet connection.

In earlier versions of Windows:

You can do this by accessing the 'Programs' option in the 'Control Panel'. Click on 'Uninstall Programs' and select 'Microsoft Office'. Right-click on the name and click 'Change'. Choose 'Online Repair' and then click 'Repair'.

The best way to ensure you don't lose data is to maintain a copy of the document off-site. You can store a copy in cloud storage services like Google Drive or OneDrive. Be sure to update your backup copy regularly to ensure there's no data loss.

What you need to know in one sheet

Boost your productivity and impress your workmates at the same time with our free Excel Shortcuts Cheatsheet for Power Users.