The file format and extension mismatch error occurs when the user tries to open certain files in Excel. Even if the user clicks Yes to open it, all information previously saved in this file will be deleted.
Change the file extension manually
Step 1. Open File Explorer> View tab> turn on File Name Extensions.
Step 2: Right-click the file and select Rename from the context menu.
Step 3: Change the extension to .xls, .xlsx or .xlsm and try to open the exel file after each name change.
Unblock at file ownership level
Step 1. Right-click the file and select Properties from the context menu.
Step 2: Select the General tab, scroll down to the Security section and click the Unblock button.
Select the “Open and Repair” option
- The Excel file may be damaged, and you can use the Open and Repair function to repair it. First, open an Excel window.
- Select the File tab.
- Click Open to open the window below.
- Select the file that has the problem.
- Then click the arrow on the Open button. Select the “Open and Repair” option. Select a repair option.
- If the “Recover” option does not solve the problem, repeat the above steps and click the “Extract data” button. Then you can click Convert To Values to extract the data from the table.
Disable Protected View
Step 1. Open Microsoft Excel> File> Options.
Step 2. Select the Trust Center tab> Trust Center Settings.
Step 3. Select “Protected Views”, uncheck “All Conditions for Protected Views” and click “OK” to save your changes.
Step 4: restart Microsoft Excel.
Open the file with a third party equivalent
Several affected users who also experienced this issue confirmed that they were finally able to open and edit the Excel file without encountering the “Does not match file format and extension” error when using the file http://windowsbulletin.com/how-to-fix-file-format-and-extension-dont-match-error-on-excel/. Free Excel. An equivalent is set and used to open the problematic file.
It turns out that this process can prevent corrupted instances from ultimately failing to open the file. If you choose to use OpenOffice, it is known to be better suited for removing corrupted attachments from Excel files if you transfer them to ODS format.
Here are some of the confirmed permissions when users find the Excel file format is incompatible with the extension error.
If the file that is having the problem is not from a trusted source, do not select it to open. Instead, scan the file with antivirus software before trying to open it.