15 Replies Latest reply on Mar 30, 2011 10:13 AM by Deepak Gupta

    SW2010 - XP Pro - Windows Explorer Thumbnails

    Brian Mears

      I recently performed a clean install of Windows XP Pro, and a clean & standard install of SolidWorks 2010 SP1.0. Until recently I've used SolidWorks 2007.


      I keep a Windows Explorer window open while I work in SolidWorks, and I drag files into SW from that window. I have the view set to Thumbnails so I can quickly and visually identify a part/assembly/drawing.


      In SW2007, these Windows thumbnails updated as I updated my SolidWorks files--after a save in SW, the thumbnail matched the most current model/assembly/drawing.


      After installing SW2010, this changed, and now thumbnails DO NOT UPDATE after the initial save. The Windows thumbnail displays the part/assembly/drawing as originally saved and does not change. Through some experimentation I was able to determine the following:


      -a restart of the computer usually 'resets' the thumbnails to the latest save

      -renaming the file will 'reset' the thumbnail to the latest save; naming it back to original returns it to the original (incorrect) image


      Using this thread (https://forum.solidworks.com/thread/18316) as a guide, I unregistered SW2010's sldwinshellextu.dll and reregistered with SW2007's sldwinshellextu.dll.  This fixed the problem.  The topic of this thread is a bit different than my issue but I suspected that they may be related; it seems that they are.


      I discussed this with my VAR's support; they tell me that this is 'predictable' and 'expected behavior'. If that were true, you all should see the same behavior. So...


      Can any of you confirm that your Windows thumbnails DO NOT update past the first save in SolidWorks?  I need a couple of responses to make sure that this indeed isn't by design.  I appreciate the help.


      Thank you,



        • Re: SW2010 - XP Pro - Windows Explorer Thumbnails
          Toby Schnaars
          Hi Brian,Nice Post!

          However, as the VAR, I just wanted to clarify that it was the change in behavior, between 2007 and 2009, that I was referring to as "expected".  Per the post in the thread you called out:

          "We observed over the lifespan of 2007 and 2008 via the feedback logs that a lot of the "random crashing" that happens in the SolidWorks File->Open dialog was related in some way to the sldwinshellextu.dll. As I mentioned above, because of the indeterministic nature of how the thumbnails work, we can never guard against such random crashes 100% and we decided to change the architecture of the thumbnail generation in 2009 so that any random crash in the image generation will never bring down the hosting exe.

          In 2009, there are now two components : one is still called sldwinshellextu.dll and the other one is sldShellExtServer.exe. If you notice, the dll in 2009 is much smaller (around 160 KB) than in 2008 (4.5 MB) and the reason is that the 2009 DLL does almost none of the work to generate the thumbnails. That work is now done by sldShellExtServer.exe. The advantage to this approach is that even if the image generation is faced with a corrupt file, it will only bring down the sldShellExtServer.exe, not your main application like sldworks.exe. "

          So when I said this was "expected behavior", I was referring more to the fact that the SolidWorks programmers purposely changed the way thumbnails are generated, and not so much to the "Windows explorer doesn’t seem to update thumbnails, at all".

          I, too, am unsure as to how long Windows takes to update the thumbnail preview, and that’s why I’m glad you posted this thread.  Hopefully someone will read this post, and will be able to shed some light on the subject.


          The only thing I was able to find was this:

          The thumbnail graphics are simply icons cached with the file and displayed in Windows Explorer by Microsoft. Microsoft decides when to update the cached icon information, and therefore when to change the display of the icons. In this case, it may be that access to the file is needed to get the icons to update. For example, selecting the file in Windows Explorer or opening and saving the file usually fixes the problem.  Sometimes the registry location where the icon information is cached becomes corrupted. We do not know the cause of this problem. To see if this is the case, run the "regedit" command, and then expand HKEY_CLASSES_ROOT. Under HKEY_CLASSES_ROOT, there must be a SldAssem.Document folder and an SLDPart.Document folder. Each folder must have a "shellex\iconhandler" folder. If the "shellex" or "iconhandler" folder is missing, the thumbnail graphics will not function.  A reboot will often be required to see the changes.

          In the Knowledge Base. 

          Any thoughts are greatly appreciated!