I had this problem for awhile and nearly pulled my hair out. What fixed it for me was to go into the 1C folder in My Documents and rename the confi.ini file. Then, I also went into steam, and in the downloads and cloud tab under settings, unchecked the synch with cloud option. I read about it somewhere online and decided to try it out, and the game started up right after that. Give it a try and hopefully it works.