Error opening excel file on sharepoint,

Question

When we open the file on Sharepoint there is an error displayed, someone can help us

"The file format and extension of “…” don't match. The file could be corrupted or unsafe. Unless you trust its source, don’t open it. Do you want to open it anyway?" YES NO Help.

Thanks and Best Regards,

Answer 1

Hi dutq,

There’s a change in Excel in the behavior of certain file types to increase security. Previously, when you tried to open an HTML or XLA file with an .XLS file extension from an untrusted location, Excel would warn about the mismatch between the file extension and content, but would still open the workbook without Protected View security. In the latest version of Excel, Excel changed handling documents that are opened from untrusted locations (such the Internet zone) which are not supported in Protected View, such as HTML/XML/XLA files. When opening HTML/XLS files without Protected View, Excel will warn about the mismatch between the file extension and HTML content, but will now open the workbook in Protected View as an additional layer of security. If you trust the workbook, you can then enable editing. XLA and XLAM files are not part of this change, they will continue to not open in Excel.

If the above does not apply to your situation, you may try the following suggestions:

1. Update Office to the latest version. With Office updated, some issues would get resolved. So it’s a good idea to keep Office up to date.
2. If you opened the Excel file on SharePoint from File Explorer, you can unblock access for individual files you know are safe. To do this:

1. Right click on the file and choose Properties.
2. On the General tab, click Unblock.
3. Click OK.

3. Use the existing Trusted Locations capabilities of Excel. Here’s an article for your reference: Trusted Locations. Although the article mentions that the method works for Excel 2016, 2013, etc., it still works for Excel 365.

You can check for version-specific information about the Trusted Locations feature and Protected View settings: Office Trusted Locations; Protected View settings. (It also applies to Excel 365).

And we need collect some information to further check it:

1. Which version of Office do you have? After starting Excel, click on File > Account, please take a screenshot of the Product Information part and share it with us.
2. Can you open the Excel file correctly if click on the “Yes” button?
3. Will you encounter this issue when opening other Excel documents on SharePoint?

Best regards,

Madoc

Answer 2

Hi dutq,

Do you still need help? Welcome to post back if you need.

Best regards,

Madoc