Response.ContentType application/vnd.ms-excel xls stopped working

I've done some pretty deep searching on this issue with no luck. It seems that in the past couple of days the output to XLS from HTML has stopped working on many legacy (read: Classic ASP) systems I support. I've been able reproduce this on multiple servers, multiple independent source code from Office 2010 through Office 2016. I've looked at everything I can think of without success so I'm curious to know if there is something I might be overlooking. I'm starting to think this may be a bad Office update that is the culprit.

Sample of what works and has been working for many years:

<%

Response.ContentType = "application/vnd.ms-excel"
Response.AddHeader "Content-Disposition", "attachment;filename=TestExcel.xls"

%>

<html>
    <body>
        <table>
            <thead>
                <tr>
                    <th>column 1 header</th>
                    <th>column 2 header</th>
                </tr>
            </thead>

            <tbody>
                <tr>
                    <td>column 1 value</td>
                    <td>column 2 value</td>
                </tr>
            </tbody>

            <tfoot>
                <tr>
                    <td>Footer 1</td>
                    <td>Footer 2</td>

                </tr>

            </tfoot>
        </table>
    </body>
</html>

What is curious is that the XLS file is in fact created but when it is opened Excel opens but not file is present.

Even more curious is that when you open the XLS file with some text editor (notepad for example) and just File->Save As it opens without issue.

xelvis42

The issue is related to Microsoft Security Update KB3115262 for Excel that was released July 12, 2016. The security update information can be found in Microsoft Security Bulletin MS16-088 - Critical.

I've found three workarounds (in my order of preference):

Instead of clicking Open, save the file and then open it
In Excel Trust Center > Trust Center Settings > Protected View, uncheck the top two options. This is potentially unsafe.
Uninstall the security update.

Below are several links regarding the issue for further perusal. https://social.technet.microsoft.com/Forums/en-US/d2d84793-9920-45e3-baef-5027a4ac1ae0/kb3170008-for-office-2016-breaks-functionality-ms16088?forum=officeitpro

https://technet.microsoft.com/library/security/MS16-088

https://salesforce.stackexchange.com/questions/131404/end-user-cannot-open-a-xls-report-exported-from-salesforce

Export HTML Table to Excel- Doesn't Open in Office 2010

You can also go to properties of the file and click Unblock.

I think is safer than change the Excel Trust Center

For Windows 10 users, add the Excel download site URL to your list of Trusted Sites in Windows 10 Internet Options > Security > Trusted Sites > Sites then download and open the Excel Workbook via your MS Edge browser.

来源：https://stackoverflow.com/questions/38466169/response-contenttype-application-vnd-ms-excel-xls-stopped-working

标签

html

excel

xls