Similar to this post: social.technet.microsoft.com/Forums/en-US/d42a81bc-96de-4af3-bc41-079e88e6ea4a
We have Citrix terminal servers running Windows 2008 R2 and attempting to force PDF files to open with Acrobat versus PDF editing software we have installed for a small subset of users. So I created a Group Policy Preference and added a OpenWith item to the Folder Options to use Acrobat as the default and linked it to a Users OU. However, if I run gpresult the OpenWith setting fails with error code 0x80070005. You can change it to not run in the user's security context which eliminates the error but then it won't actually do anything.
The problem seems to be that when a user sets another program as their default via Windows Explorer the permissions on HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.pdf\UserChoice get changed so that the user is specifically denied the ability to set that key. Remove the special permissions added and the group policy succeeds and changes it back to the default ... until the user changes it back (intentionally or otherwise) and the permissions are changed again.
Any ideas here?