Keyword:

Unable to upload multiple files in SharePoint 2010

Object reference not set to an instance of an object error occur when uploading multiple files in SharePoint 2010

STSUpld exception error when uploading multiple files in SharePoint 2010

NullReferenceException when uploading multiple files in SharePoint 2010

Problem uploading multiple files in SharePoint 2010

Fail uploading multiple files in SharePoint 2010

Root Cause:

You probably have customized your system masterpage which contains html input element with type=”button” without accesskey attribute on it.

All input element of the type button require accesskey attribute.

        image

See the end of this message for details on invoking
just-in-time (JIT) debugging instead of this dialog box.

************** Exception Text **************
System.NullReferenceException: Object reference not set to an instance of an object.
   at STSUpld.UploadCtl.GetFormInformation()
   at STSUpld.UploadCtl.OnLoad(EventArgs e)
   at System.Windows.Forms.UserControl.OnCreateControl()
   at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)
   at System.Windows.Forms.Control.CreateControl()
   at System.Windows.Forms.Control.WmShowWindow(Message& m)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
   at System.Windows.Forms.ContainerControl.WndProc(Message& m)
   at System.Windows.Forms.UserControl.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ActiveXImpl.System.Windows.Forms.IWindowTarget.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

************** Loaded Assemblies **************
mscorlib
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.5466 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/Microsoft.NET/Framework/v2.0.50727/mscorlib.dll
—————————————-
stsupld
    Assembly Version: 14.0.0.0
    Win32 Version: 14.0.6106.5001
    CodeBase: file:///C:/PROGRA~1/MICROS~1/Office14/STSUPLD.DLL
—————————————-
System.Windows.Forms
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.5468 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Windows.Forms/2.0.0.0__b77a5c561934e089/ System.Windows.Forms.dll
—————————————-
System
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.5467 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System/2.0.0.0__b77a5c561934e089/System.dll
—————————————-
System.Drawing
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.5467 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Drawing/2.0.0.0__b03f5f7f11d50a3a/ System.Drawing.dll
—————————————-
stsupld.intl
    Assembly Version: 14.0.0.0
    Win32 Version: 14.0.4761.1000
    CodeBase: file:///C:/PROGRA~1/MICROS~1/OFFICE14/1033/stsupld.intl.DLL
—————————————-
Accessibility
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.4927 (NetFXspW7.050727-4900)
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/Accessibility/2.0.0.0__b03f5f7f11d50a3a/Accessibility.dll
—————————————-
Microsoft.mshtml
    Assembly Version: 7.0.3300.0
    Win32 Version: 7.0.3300.0
    CodeBase: file:///C:/Windows/assembly/GAC/Microsoft.mshtml/7.0.3300.0__b03f5f7f11d50a3a/ Microsoft.mshtml.dll
—————————————-
CustomMarshalers
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.5420 (Win7SP1.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_32/CustomMarshalers/2.0.0.0__b03f5f7f11d50a3a/ CustomMarshalers.dll
—————————————-
System.Web
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.5456 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_32/System.Web/2.0.0.0__b03f5f7f11d50a3a/System.Web.dll
—————————————-
System.Xml
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.5420 (Win7SP1.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Xml/2.0.0.0__b77a5c561934e089/System.Xml.dll
—————————————-

************** JIT Debugging **************
To enable just-in-time (JIT) debugging, the .config file for this
application or computer (machine.config) must have the
jitDebugging value set in the system.windows.forms section.
The application must also be compiled with debugging
enabled.

For example:

<configuration>
    <system.windows.forms jitDebugging="true" />
</configuration>

When JIT debugging is enabled, any unhandled exception
will be sent to the JIT debugger registered on the computer
rather than be handled by this dialog box.

Solution:

In your system masterpage/custom masterpage, make sure all html button type elements have accesskey attribute and assign some value to it.
e.g. <input name”X” class=”Y” type=”button” accesskey=”_”>