I am wondering if anyone else out there had a poor experience as I did with x64 of SW2009 sp5.0 running Vista 64. We had been running SP 4.0 with a hotfix that took care of a problem between Microsoft Office and SolidWorks. We had some other lingering issues including users crashing but not as frequent as sp before 4.0. I upgraded everyone to SP5.0 in hopes that it would help with the rest of the issues we have had. I followed the SolidWorks procedure of removing the hotfix since it was supposed to be rolled up into the sp 5.0. When I did the upgrade to sp 5.0 it was a disaster for us at least with the 64bit machines which is the majority of my users now. We made the decision to drop back to 4.0 and to achieve this I went out on a limb and reset my share for the image back to the SP4.0 image. When the users executed SolidWorks it went into an update mode to roll back to sp 4.0. Here is where the strange part begins. The result was two service packs loaded on the same machine. Two icons, one SP4.0 and one SP5.0. if you open the application for both and go to the help about you can clearly see the machines have both sp's loaded along with two installation directories. If you run SP 5.0 it crashes constantly if you run SP4.0 it runs all day 7 days a week with out crashing. We had an issue with SP4.0 and the hole wizard running slow and that is now gone under this new SolidWorks cocktail. My users are claiming that the files open faster as well. I was going to wipe the installs and give them clean installs of SP4.0 but instead at a request of the users and given the results I am going to leave it as is. Until this strange little exercise we have never been able to get SolidWorks to run this well. With that being said I would be shocked not to see some strange things pop up withing the next few weeks but so far so good.