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When attempting to open or edit an Excel file in MS Office 2003/2007/2010/2013/2016/2019, several users have reported about receiving ‘Excel cannot open the file because the file format or file extension is not valid’ error message.
The complete error message reads as follows:
"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."
Figure 1 - Excel File Extension not Valid Error Message
In this post, we will outline common reasons behind the error and discuss some effective solutions to resolve the .xlsx error. We will also explain how you can get your MS Excel data back.
The error may occur due to any of these reasons:
Try the below-mentioned methods to resolve the ‘Excel cannot open the file because the extension is not valid’ error, and regain access to the Excel worksheet:
MS Excel saves workbooks as XLSX or XLS file format by default. In Excel 2003 and earlier versions, files are saved as XLS. On the other hand, the files get saved in XLSX file format in Excel 2007, 2010, 2013, 2016, and 2019 versions. You may encounter the error ‘Excel file extension not valid’ due to an incompatible Excel file extension.
To resolve the issue, try changing the respective Excel version's default file format to any other file format that MS Excel supports. To do so, execute the following steps:
Figure 2 - Select Export Option in Excel
Figure 3 - Change the Excel File Type
Now check if Excel can open the file.
If you encounter the ‘Excel file extension not valid error’ when trying to open an unsaved workbook, try these steps to recover the unsaved workbook:
Figure 4 - Recover Unsaved Workbooks Option in Excel
The ‘Open and Repair’ is a built-in Excel utility, designed to repair damaged Excel files. To use it, perform the following steps:
Figure 5 - Excel Open and Repair Feature
Figure 6 - Repair the Microsoft Excel File
If the above manual methods fail to fix the “Excel cannot open the file '(filename)'.xlsx…” error, repairing the file using a specialized Excel repair software may help.
Stellar Repair for Excel software is purpose-built to repair corrupt XLS and XLSX files. The software also helps restore entire file items such as table, chart, chart sheet, image, cell comment, formula, sort, filter, etc., maintaining the original format of the MS Excel files.
Check out the video to know how to repair corrupt Excel file by using Stellar Repair for Excel:
Several manual methods, such as the ones discussed in this post, can help fix the ‘Excel cannot open the file ‘(filename)’.xlsx’ error. We recommend using the Stellar Repair for Excel software discussed above to resolve the error when other methods fail. Use the demo version of the software to ascertain its functionality by previewing the recoverable Excel data.
Stellar Repair for Excel Stellar Repair for Excel is the best choice for repairing corrupt or damaged Excel (.XLS/.XLSX) files. This Excel recovery software restores everything from corrupt file to a new blank Excel file.