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How can we improve Excel for Windows (Desktop Application)?

HTML formatted files (with an XLS extension) no longer opened

Since a recent update HTML formatted files with .xls extension are no longer opened. When downloading such a file Excel opens but does not open the file anymore, it just shows a blank screen, no error message. This used to work for years and was very easy to create reports from our intranet by just sending HTML files with Excel headers out. Because of this we now have to re-engineer all reports, please bring the functionality back.

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Ruud shared this idea  ·   ·  Flag idea as inappropriate…  ·  Admin →
completed  ·  Dan Battagin [MS XL] responded  · 

Hi all,

We’ve released a fix for this issue. I’m copying the official release notes for it here, as this is part of several different updates to several different versions of Office:

The Excel team has released a change in behavior in today’s security update for Excel 2010, 2013, and 2016. 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. The behavior of .xla and .xlam files will remain the same.

How do I get the update? It depends on which version of Office you have.
• Office 365 subscription (Click-to-Run)—install the latest updates
• Windows Installer version (MSI)—you could wait about a week for the next security update for MSI, and it will update automatically. Or, to get the fix today, use the Download Center to get the KB for your version of Office:
o Office 2016:
o Office 2013:
o Office 2010:

Issue recap:
The Excel team has made a change in the behavior of certain file types to increase security. This change came in the security updates KB3115262, KB3170008, and KB3115322. Previously, when you tried to open an HTML, XLA, or XLAM 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. After the security updates Excel no longer will open the workbook because these files are not compatible with Protected View and there is no warning or other indication it was not opened.

Workarounds for .xla and .xlam files:

Thank you for your patience and input—community suggestions drove our decision to change this behavior in a way we hope will be much better for your workflows!

Hope that helps!

Dan [MS]

Hi Ruud,

We know about this issue and are working on a fix.

For more information, as well as three workarounds until the fix is released, please see this page:

Dan [MS}


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