IE10 slow on file download due to MS Office Protocol Discovery OPTIONS requests. Any workaround? - internet-explorer-10

Question

We are facing an issue with Internet Explorer 10/11. At some moment during file download IE hangs for a while (up to 1 minute) and then opens file as expected (this is relevant only for MS Office file types). Other browsers work without any issues (including IE7, IE8, Firefox, Chrome, etc). This is somehow related to Microsoft Office Protocol Discovery, so our server returns 405 for such requests to tell IE that there is no support for this protocol. Microsoft actually has an article about similar issues:
The WebClient service also assumes that if the target host does not
support PROPFIND that it will return an error status like 405 Method
Not Allowed
Here is relevant portion of httpd.conf:
# Returning 405 for HEAD requests is not a great idea, we use it here just for testing
RewriteCond %{REQUEST_METHOD} ^(OPTIONS|PROPFIND|HEAD)$ [NC]
RewriteCond %{HTTP_USER_AGENT} ^Microsoft\ Office\ Protocol\ Discovery [OR]
RewriteCond %{HTTP_USER_AGENT} ^Microsoft\ Office\ Existence\ Discovery [OR]
RewriteCond %{HTTP_USER_AGENT} ^Microsoft\-WebDAV\-MiniRedir.*$
RewriteRule .* - [R=405,L]
Using "attachment" in Content-disposition header is not an option (we want MS Office plugin for IE to open files in a browser window without a lot of additional dialogue boxes, etc).
Delay during file download is clearly visible in Wireshark:
No. Time Source Destination Protocol Length Info
4 0.012920000 172.17.0.9 172.17.0.182 HTTP 348 GET /service/download/094444448003f6ae HTTP/1.1
57 4.652657000 172.17.0.182 172.17.0.9 HTTP 1371 HTTP/1.1 200 OK (application/msword)
62 11.291203000 172.17.0.9 172.17.0.182 HTTP 208 OPTIONS /service/download/ HTTP/1.1
64 11.292579000 172.17.0.182 172.17.0.9 HTTP 580 HTTP/1.1 405 Method Not Allowed (text/html)
72 11.295662000 172.17.0.9 172.17.0.182 HTTP 208 OPTIONS /service/download/ HTTP/1.1
74 11.297493000 172.17.0.182 172.17.0.9 HTTP 580 HTTP/1.1 405 Method Not Allowed (text/html)
82 11.310690000 172.17.0.9 172.17.0.182 HTTP 208 OPTIONS /service/download/ HTTP/1.1
84 11.312993000 172.17.0.182 172.17.0.9 HTTP 580 HTTP/1.1 405 Method Not Allowed (text/html)
94 32.345213000 172.17.0.9 172.17.0.182 HTTP 203 HEAD /service/download/094444448003f6ae HTTP/1.1
98 32.346555000 172.17.0.182 172.17.0.9 HTTP 60 HTTP/1.1 405 Method Not Allowed
104 53.357503000 172.17.0.9 172.17.0.182 HTTP 202 OPTIONS /service/download HTTP/1.1
106 53.358397000 172.17.0.182 172.17.0.9 HTTP 579 HTTP/1.1 405 Method Not Allowed (text/html)
114 53.380199000 172.17.0.9 172.17.0.182 HTTP 222 HEAD /service/download/094444448003f6ae HTTP/1.1
117 53.381414000 172.17.0.182 172.17.0.9 HTTP 60 HTTP/1.1 405 Method Not Allowed
The back-end is a Spring application deployed to Tomcat. Relevant headers look like this:
response.setContentType(mimeType + ";charset=UTF-8");
response.setHeader("Content-Transfer-Encoding", "binary");
response.addHeader("Content-disposition", "inline;filename=sample_document.doc");
What is IE waiting for between OPTIONS requests? Is it possible to debug somehow?
Note: This was confirmed for multiple workstations in our network running Windows 7, Office 2010 and IE10/11. Some machines show significantly better performance in this task than others.

Answer 1

We had something which sounds similar a year and a bit ago. We added the following stanza to the Apache config for the sub-site to "fix" things ...
# IM163264 18/02/2013 - disallow OPTIONS/PROPFIND to stop Windows/IE treating
# this as a webdav store and being slow.
<LimitExcept GET HEAD POST>
deny from all
</LimitExcept>
My theory was that IE was trying to act as a WebDav client - blocking anything but GET/HEAD/POST felt like a sledgehammer but made things work for the customers.