I'm seeing an issue with the Windows 29.9.14 build when it is first launched. An error box with the title "Assertion failure. Do you want to Debug" pops up with the following message:
AI exception from ErrorThrower declared in file: D:\J\ws\ilst_main\app\Suites\FxIllustratorDiagnosysPrefs.cpp line: 117
The first time I saw the error the 29.9.14 beta wouldn't launch regardless if I clicked the "yes" or "no" buttons. After rebooting and clicking the "no" choice Illustrator would finish launching.
It's a strange issue, considering I didn't have any extra drives attached at the time, just the boot disc drive in the computer (drive C).