I'm having some api.dll issues and am wondering which is the best version of the UIAutomationCore.dll to use. I'm currently using 6.0.5840.16386. Is there a "better" one out there? Thanks.

there is also 6.0.6001.18000 which is a bit newer than your version.

 

Some say this newer version may fail at times for some users, but it hasnt failed on me since ive been using it, which is about 2 years now.