[FIXED] Excel Cannot Open the File Because the File Format or File Extension Is Not Valid

Do you get an error message: Excel cannot open the file **.xlsx because the file format or file extension is not valid? Quick fixes and advanced solutions are offered here to help you fix this error on Microsoft Office 2007, 2010, 2013, or 2016. Besides, if you lost Excel files, you can download EaseUS data recovery software to get additional help.

Table of Contents

3 Fixes for Excel Cannot Open the File Because the Extension Is Not Valid

The file format of an Excel worksheet is .xlsx or .xls. Whenever the user opens any file, it is opened with the same extension. However, some users may encounter an error when trying to open or edit an Excel file in Office 2003, 2007, 2010, 2013, 2016, 2019, and 365. The error message displays, "Excel cannot open the file because the extension is not valid".

This article will provide you with three effective solutions to resolve excel cannot open the file because the file format or file extension is not valid. You can change the file extension, use the Office repair utility, or use one of the best data recovery software to repair Excel files. 

Workable Solutions Step-by-step Troubleshooting
Fix 1. Change File Extension Open Microsoft Excel and go to "File" > click Export and choose Change File Type...Full steps
Fix 2. Use Open and Repair Start Office Excel > click File and Open > select the inaccessible Excel file...Full steps
Fix 3. EaseUS File Repair Tool Launch EaseUS Data Recovery Wizard, and then scan the corrupted or damaged Excel files...Full steps

Error "Excel Cannot Open the File Because The File Format or File Extinction Is Not Valid"

Sometimes, when you try to open or edit an Excel file on Microsoft Office 2003, 2007, 2010, 2013, 2016, 2019, or 365 you may encounter the following problem:

"Excel cannot open the file 'filename.xlsx' because the file format or file extension is not valid. Verify that the file has not been corrupted and that the file extension matches the format of the file."

Error - Excel can't open the file  because the extension is not valid

It usually indicates the file is not compatible with the Excel version of the file that has come corrupt or damaged. Here, we will show you all the possible solutions, and you can try them respectively until fixing the issue. Before you take the solutions, check whether Excel can be used normally.

Step 1. Press Windows+R key, type excel.exe /safe, and click "OK". Loading Excel without templates and add-ins allows you to see if the program works as it should or if it is corrupted.

Step 2. If Excel opens normally, check for any add-ins that are causing problems in Excel. Disable the add-ins and click on the "OK" button. Then, restart Excel to check if the problem is fixed. If not, move on to the fixes below.

check your excel application

There are three useful solutions in total to solve the Excel cannot open file issue. Besides, two methods are provided to recover Excel when the file format or file extension is not valid. 

[Related reading: Excel not saving changes]

Fix 1. Change the Excel File Extension to Open It

Many times, this error occurs due to the incompatible file extension of the Excel file. MS Excel saves Excel workbooks as XLSX or XLS files by default. Excel 2003 and earlier versions save files like XLS, whereas Excel 2007 and later versions like Excel 2010, Excel 2013, Excel 2016, and 2019 save files in XLSX file format. You can change the default file format for the corresponding Excel version to any other file format supported by MS Excel.

Step 1. Open Microsoft Excel and go to the "File" tab.

Step 2. Click "Export" and choose "Change File Type".

Step 3. Change the file extension to any other file format that MS Excel supports and click "Save As". Then, Check if Excel can open your file or not.

Change file extendsion to fix excel cannot open the file because the extension is not valid

Fix 2. Open Excel File Using the Open and Repair Feature

The "Open and Repair" is a built-in easy-to-handle MS Excel utility that allows you to correct the error Excel cannot open the file because the file format or file extension is not valid.

Step 1. Start Office Excel. On the File menu or the Microsoft Office button, click "Open".

Step 2. In the Open dialog box, click to select the inaccessible Excel file.

Step 3. Click the down arrow on the Open button, and then click "Open and Repair". Microsoft Office will then start to check the Excel document and repair problems or corruption it found. 

Fix 'Excel cannot open this file' error with Open and Repair feature.

Fix 3. Use EaseUS File Repair Tool to Fix Excel Cannot Open the File

If the "Excel cannot open the file because the extension is not valid" problem is caused by file corruption rather than file compatibility, you need a professional file repair program to help you fix the problem. 

EaseUS Data Recovery Wizard is an all-in-one tool that can help recover deleted files and restore corrupt files easily and efficiently. It can help to repair corrupted JPEG/JPG or recover damaged MP4 and MOV files on both Windows and Mac computers. This professional MS Office Excel file repair tool has the following salient features.

Why You Choose EaseUS Data Recovery Tool

  • Recover corrupted Excel files in XLSX/XLS formats
  • Repair single or multiple Excel file without quantity limit
  • Supports MS Excel 2019, 2016, 2013, 2010, 2007, 2003, XP, 2000, 97, and 95 versions
  • Real-time preview of repairing corrupted Excel file

Now, download the EaseUS MS Office document repair tool and follow the step-by-step guides below to repair damaged Excel files with three steps.

Step 1. Select a location to start finding corrupted Excel files

Launch EaseUS Data Recovery Wizard, and then scan the corrupted or damaged Excel files.

repair Excel file - 1

Step 2.  Scan for the corrupted Excel document

Find the damaged files through the filter, file path, search, etc.

repair damaged Excel files

Step 3.  Repair and save the Excel file to a secure location

Double-click the corrupt excel file, and this program will automatically repair corrupted and damaged Excel files. Click "Recover" to save the repaired Excel files to a safe location.

Save repaired Excel files

Recover Excel File When the File Format or File Extension Is Not Valid

If your unsaved Excel file cannot be opened because the file format or file extension is not valid, how to recover unsaved Excel files? Try the two ways below. 

1. Restore Unsaved Excel Wordbook from Previous Versions

This method can only restore lost files to a previous version. It means that you may lose some changes you may have made to the document.

Step 1. Right-click the inaccessible Excel document and choose "Properties".

Open Excel properties

Step 2. Open the "Previous Version" tab to list all the previously stored versions of the Excel file.

Step 3. Choose the right version and click "Restore" to retrieve the document.

recover unsaved excel from previous versions

2. Restore Unsaved Excel File Using AutoRecover

This method only works when you have turned on the AutoSave feature in Office Excel. And it's also helpful for recovering unsaved Word documents

Step 1. Open Office Excel and go to the "File" tab > click "Info".

Step 2. Besides Manage Versions, you'll see all autosaved versions of your file.

Restore cannot be opened Excel file from previous version.

Step 3. Open the file in Excel and click "Restore". 

Restore Excel file that cannot be opened

Step 4. Save the file with another file name and set the extension as .xlsx.

Worthy Tips to Prevent Excel File from Loss

There are many ways to prevent data loss. If you have lost important Excel files due to careless deletion, hard drive formatting, or virus attack, you can use the data recovery tool to retrieve lost data. There is another crucial point to avoid data loss, which is backing up your Excel file at any time. 

1. Recover Deleted or Lost Excel File with File Recovery Software

Except for restoring unsaved Excel caused by Excel crashes when saving or other reasons, many users need to recover lost excel spreadsheets caused by accidental deletion, OS crash, hard drive damaged/corrupted, or lost partition. On this occasion, you have to resort to a professional file recovery tool for help. And EaseUS file recovery software is worth trying. It allows you to recover deleted DOC/DOCX, XLS/XLSX, PPT/PPTX, PDF, CWK, HTML/HTM, INDD, EPS, etc. with a few clicks.

Give it a try to get your lost Excel back immediately:

Step 1. Select location and click "Scan"

Choose the drive X: or a specific folder on Desktop or somewhere else where you lost the excel files, and then click "Scan".

select a location and click scan

Step 2. Locate your excel files

To quickly find the Excel files from the scan results, click on the "Filter" on the top area, choose "Excel", and click tree view on the left side. Or, search .xls or .xlsx in the Search box. 

scan excel files

Step 3. Preview and recover

You can double click on the Excel file to preview its integrity. Finally, select the desired Excel files and click "Recover".

preview and recover excel files

2. Back-Up Excel File Automatically 

If you need to modify and change your worksheet frequently, turning on the AutoSave feature is also necessary. Or you can also copy and backup your file to another safe location manually in case of accidents.

Turn on AutoSave feature in Excel

Final Words

"Excel cannot open the file '(filename)' .xlsx because the file format for file extension is not valid" is a usual error that you can face while opening an Excel file. With the help of the above methods, this error can easily be resolved without data loss.

If Excel cannot open the file problem is due to file corruption, EaseUS file repair tool can help you fix and recover the Excel file with a few clicks in a short time. It is good at repairing photos, videos, documents, and other files on the hard drive, SD card, memory card, or any other storage medium. No matter they are lost or existed on your devices. It's worth a shot.

Excel Cannot Open The File Because the Extension Is Not Valid FAQs

The following four frequently asked questions are highly related to Excel cannot open the file because the file format or file extension is not valid. If you also have any of these problems, you can find the methods here.

How do I fix the file format or file extension is not valid?

You can try to fix Excel cannot open the file because the file format or file extension is not valid by changing the file extension:

Step 1. Open your Excel file. On the taskbar, select "File". Then select "Options" > "Export" > "Change File Type".

Step 2. You can directly change the file extension depending on the version of Excel installed.  Click "Save As". Then, check if the error "Excel cannot open the file" is resolved or not.

How do I recover an Excel file format or file extension that is not valid?

You can restore Excel file format, or the file extension is not valid from previous versions.

Select the damaged file. Right-click it and click "Properties" > "Previous Version". A list of previous versions will appear; you need to select the option you are interested in and click "Restore" to recover. Previous versions come file File History or from restore points.  

What does file extension not valid mean?

"Excel cannot open the file '(filename)' .xlsx because the file format for file extension is not valid" is a common error that many users may encounter while opening a .xlsx file, especially when opening a spreadsheet received through an email. The possible reasons for this issue might be:

  • The Excel file is corrupt or damaged.
  • The Excel file is not compatible with the version of MS Excel you're using.

Why can't I open an XLSX file?

When the Excel file is corrupted, not compatible with the Excel version, infected by the virus, or received by email are the common cause of "Excel cannot open the file because the file format or file extension is not valid" problem. Any of these problems appear, you could not open an XLSX file. 

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Updated by Cedric

Cedric Grantham is one of the senior editors of EaseUS who lives and works in Chengdu, China. He mainly writes articles about data recovery tutorials on PC and Mac and how-to tips for partition management. He always keeps an eye on new releases and likes various electronic products.

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Written by Roxanne

Roxanne is one of the main contributors to EaseUS and has created multiple posts on digital devices like PCs, Mobile phones, tablets, Mac, etc. She loves to share ideas with people of the same interest.

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