Summary: This post discusses workarounds lớn resolve sầu the ‘Excel cannot open the file because the extension is not valid’ error. The error may occur if you’re using an unsupported Excel tệp tin format or the tệp tin is corrupt. If the Excel tệp tin is severely corrupt, you can use an Excel repair tool to lớn fix it và recover the data.Quý Khách sẽ xem: Lỗi excel cannot open the tệp tin because the file format or tệp tin extension is not valid


When opening an older version of an Excel file in a newer version, you may encounter the “Excel cannot open the tệp tin because the extension is not valid” error. This happens if you have accidentally renamed the tệp tin with a different tệp tin format or an incorrect tệp tin extension. Also, you may get the ‘Excel cannot open the file’ error if the file has become unreadable or corrupted.

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This is how the complete Excel error message looks like:

“Excel cannot open the file filename.xlsx because the tệp tin format or tệp tin extension is not valid. Verify that the file has not been corrupted & that the file extension matches the format of the file.”


How khổng lồ Fix ‘Excel Cannot mở cửa the File Because the Extension Is Not Valid’ Error?

Try any of these workarounds to fix the error and regain access lớn your Excel tệp tin data:

Workaround 1 – Change the Default File Format

By mặc định, an Excel tệp tin is saved in .xlsx or .xls tệp tin format. Trying lớn open the file with a different or incorrect extension may cause the ‘Excel cannot open the file because the extension is not valid’ error. To fix the error, try changing the Excel default file format by following these steps:

Note: Take a backup of the Excel file that you cannot open and try the steps on the backup copy.

In Excel 2010 & newer versions, click on the File menu.

Note: For Excel 2007 and earlier versions, clichồng on the Office button.

In Info screen that appears, cliông xã on Options. In ‘Excel Options’ window, under Save workbooks section, click on the Save files in this file format: drop-down. Select a tệp tin format (i.e., the one supported by your Excel version).

Cliông xã OK.

Check if you can open your Excel tệp tin. If not, try the next workaround.

Workaround 2 – Edit the Excel File Permissions

You may receive sầu the ‘Excel tệp tin format or file extension is not valid’ error if you laông xã sufficient permissions to lớn open the tệp tin. Usually this happens when you try to open an Excel tệp tin received from some other user. Follow these steps khổng lồ change the file permissions & see if it fixes the problem:

Right-clichồng on the file that won’t open & clichồng Properties.In the tệp tin properties dialog box, clichồng the Security tab và then hit the Edit button.

When the file’s permissions dialog box appears, cliông chồng on the Add button.

Click on the Advanced button from the ‘Select Users or Groups’ window.

Excel will danh mục any unsaved files. Try opening the file và save sầu it. If this doesn’t work, skip to the next workaround.

Workaround 4 – Repair the Workbook

If none of the above workarounds has worked for you, chances are that the Excel file has become corrupted. Try lớn repair the tệp tin using the Excel inbuilt ‘Open và Repair’ utility by following these steps:

In your Excel application, cliông xã on File > Open.In the ‘Open’ dialog box that pops-up, select the Excel tệp tin you want to lớn repair and click the arrow next to the xuất hiện button.
From the dropdown danh mục, select Open and Repair.Excel will ask you to lớn attempt lớn repair the tệp tin or extract data from it. Click Repair to retrieve maximum data. If the Repair option fails, click on Extract Data khổng lồ recover the data without formulas and values.

If the ‘mở cửa & Repair’ utility doesn’t help fix the corrupted file and/or recover the data, use an Excel repair tool such as Stellar Repair for Excel khổng lồ regain access to lớn your file and its data.

Stellar Repair for Excel software can help repair severely corrupted XLS and XLSX files. Also, it helps recover all the file components, including tables, pivot tables, cell comments, charts, chart sheets, images, formulas, etc., without impacting the original structure of the Excel file. 

To learn how the software works, read this: How to repair corrupt Excel file using Stellar Repair for Excel?


You may encounter the error ‘Excel cannot open the file because the extension is not valid’ when opening a workbook with a different tệp tin format or an incorrect tệp tin extension. Also, the error may occur if the Excel tệp tin has turned corrupt. This article has covered some of the most effective sầu workarounds to lớn resolve sầu the error. But if nothing works, you can try khổng lồ repair the Excel file & retrieve sầu its data using the Stellar Repair for Excel software.


Q. I have sầu an Excel file saved on my system. I get the error message ‘Excel cannot open the file filename.xlsx because the tệp tin format or tệp tin extension is not valid’ when trying lớn open it. Can I get baông chồng all my data using the Excel repair tool?

A. Stellar Repair for Excel displays a pđánh giá of all the recoverable data. You can get bachồng all the Excel tệp tin data shown in the pĐánh Giá window.

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Q. I downloaded the repair tool, but it says, “File is severely corrupted, cannot be previewed.” What should I vì chưng next?

A. This message appears if your Excel file has turned severely corrupt. Liên hệ the support team at Stellar to lớn get further assistance.