Unable to find the object Sys.Browser("firefox").

Hi,

I would recommend to upgrade TestComplete to the latest v.12.10 and install FireFox patch for v.50 as there is a chance that patch for FF49 does not work for FF49.0.2.

Edit: You may try to apply patch for FF50 to your existing version of TC - this might be possible according to https://community.smartbear.com/t5/TestComplete-General-Discussions/It-is-joke-with-patch-of-Firefox-Support/td-p/131183.