Final Edit-
Temporary workaround: click iOS Simulator > Reset Content and
Settings… and run again.This error message may reappear at random. For me, it happens when I
launch a different application. There are several threads in Apple dev
forums and in StackOverflow about this problem, but none have a
definitive answer. This seems to be a SDK error to be fixed in the
next Xcode version.Updated: October 3.
CREDIT – Please check this answer – Xcode 5 Error CertUIFramework.axbundle
Further Edit
Although this was potentially the issue resolution at the time. I believe some of the newer answers below relating to the better touch tool are in fact the correct resolutions.