Lỗi Excel Cannot Open The File Because The File Format Or File Extension Is Not Valid

Summary: This post discusses workarounds to resolve sầu the ‘Excel cannot open the tệp tin 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 khổng lồ fix it and recover the data.

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When opening an older version of an Excel tệp tin 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 file with a different file format or an incorrect file extension. Also, you may get the ‘Excel cannot open the file’ error if the file has become unreadable or corrupted.

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 và that the tệp tin extension matches the format of the file.”


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

Try any of these workarounds to fix the error & regain access khổng lồ your Excel file data:

Workaround 1 – Change the Default File Format

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

Note: Take a backup of the Excel tệp tin that you cannot open và try the steps on the backup copy.

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

Note: For Excel 2007 và earlier versions, cliông chồng on the Office button.

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

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

Workaround 2 – Edit the Excel File Permissions

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

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

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

Xem thêm: Bỏ Page Break Trong Excel 2010, Hướng Dẫn Cách Xóa Ngắt Trang Trong Excel


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

Excel will list any unsaved files. Try opening the file and save it. If this doesn’t work, skip lớn the next workaround.

Workaround 4 – Repair the Workbook

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

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

If the ‘xuất hiện and Repair’ utility doesn’t help fix the corrupted tệp tin and/or recover the data, use an Excel repair tool such as Stellar Repair for Excel to regain access to 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 tệp tin components, including tables, pivot tables, cell comments, charts, chart sheets, images, formulas, etc., without impacting the original structure of the Excel tệp tin. 

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


You may encounter the error ‘Excel cannot open the tệp tin because the extension is not valid’ when opening a workbook with a different file 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 workarounds to lớn resolve sầu the error. But if nothing works, you can try to lớn repair the Excel file and 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 tệp tin filename.xlsx because the tệp tin format or file extension is not valid’ when trying lớn open it. Can I get bachồng 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 baông xã all the Excel tệp tin data shown in the pĐánh Giá window.

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

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