Help Required - Upload Multiple Documents functionality sometimes disappears in SharePoint 2010

Question

Hi All,
We have a web application created in SharePoint 2010 & there we were facing an issue of not able to Upload multiple documents. After doing search on google, we have found that
pre-requisites for this functionality to be working properly are as follows:
Client Integration needs to be enabled for the web application.
The STSUpld.UploadCtl IE add-in must be enabled. (located in C:\Program Files (x86)\Microsoft Office\Office12)
The 32 bit version of Internet Explorer. The 64 bit version does not support it and neither do other, non IE, browsers.
Office 2003 or newer on the client.
After meeting all the above requirements, We are now able to see the Upload Multiple Documents link but we are failing in below 2 scenarios:
On some machines it is working fine & on some it is not.
On some machines, this option is available for sometime & sometimes it disappears.
If any one of you have experienced the same problem, then please help us with your valuable suggestions & possible solution for it.

Answer 1

Hi Manish,
We've just been experiencing your initial issue with Office 2007 clients not being able to use the multi-file upload functionality.  Sure enough....turning on presence information in Central Admin fixes the issue.  The strange thing is though that
when presence is turned off, Office 2003 and 2010 clients still work fine and it's only 2007 clients that fail.  Also this issue appeared to only exist for us inside applications that have been upgraded from MOSS2007 to SP2010.  Any new applications
of even new site collections within an upgraded application worked fine across all 3 Office versions.
Coincidently, we're also experiencing the more recent issue you've come across with files not uploading after clicking OK in the ActiveX.  Nothing happens.  Office 2010 clients work fine but 2003 and 2007 clients just don't upload the selected
files.  We've found a workaround which "fixes" the issue but brings it's own set of problems so it's not ideal.  Here's what we've done...
1. Open IIS, and navigate to the web where you want to use multi-file upload
2. Select Handler Mappings and Add Script Map
3. Set Request Path - shtml.dll
4. Set Executable - C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\ISAPI\SHTML.dll
5. Set the name to something meaningful - Multi File Upload
6. Leave the Request Restrictions as default
This should fix the issue with files not uploading but unfortunately it also prevents SharePoint Designer from accessing the site.  For the application where we desperately need multi-file upload we can manage without SPD access so it's not the end
of the world but not ideal.  We've actually got an outstanding incident logged with Microsoft to resolve this issue but they've yet to find a solution for us.  We suggested to MS that we update authentication to Kerberos from NTLM and retry as we
seem to be getting 401 errors in the call stack so thought that could be related.  We've not yet configured Kerberos so I'm not sure whether this is a solution or not.
One other point worth mentioning is that SharePoint Designer 2010 (which is free) installs the latest version (14) of the Upload ActiveX and with this installed the uploads work as expected.  Also if you have Silverlight and SPD2010 installed then you
get a Silverlight control to do the upload which also works fine.  Again, not ideal as rolling out SPD 2010 to affected clients isn't really a suitable solution.
Sorry I can't be any more help.  Hopefully my findings might point you in the right direction.  If you do find a solution (other than the IIS handler mapping) then please re-post here,
Good luck,
Ben