Well, I’ve had an interesting morning. A couple of days ago I uninstalled Office web apps from a server to try and fix the known issue where Office Web Apps breaks Content Query Web Part (CQWP) document links (see the response from Lily Wu). The following morning, I had a user come to me and indicate they were having problems opening the datasheet view in a list or document library. Yesterday I had another user come and tell me that she was having the same symptoms with most documents in a document library… and I started smelling trouble.
This morning I decided to investigate the issue further – No errors in SharePoint ULS, no errors on the client machine event logs, so it was difficult to see what the cause might be. All of the problems seemed to resolve around Office Thick Client interactivity, and I remember back in 2007, there was a few reports of unexpected crashes with users who had more than one generation of office products installed, so I checked – Everyone reporting the issue had one or more Office 2007 products deployed (like Visio or MS Project) as well as the standard Office 2003 suite…
In the end, the fix was pretty simple. The issue was being caused by duplicate instances of OWSSUPP.DLL (one in C:\Program Files\Microsoft Office\OFFICE11 and one in C:\Program Files\Microsoft Office\OFFICE12) – the file formats that were having issues were all Office 11 file types (that is, Office 2003) – So I changed the OWSSUPP.DLL file in the Office12 folder to OWSSUPP_DLL.zzz, restarted IE and the problem disappeared.
I also tried deregistering both files and just re-registering the one for 2003 using regsvr32.exe (some limited success with one of the users, but not success for all who were experiencing the symptoms) and also resetting IE7’s settings (no success at all). Renaming the file and restarting IE was the only way to go.
Hope this helps someone experiencing the same problems in SharePoint 2010.