I had a problem with the Blizzard Battle.net launcher that simply wouldn’t start and soon enough embarked on the quest to look for the answer. Unfortunately, Blizzard support forums had no answer for my problem, but what was even more worrying, the advice there given were downright horrible. After suggesting to people to delete their WTF folders, reinstall World of Warcraft in entirety or – one of the most horrible ones – to reinstall their entire operating system(!) the majority of them still had this specific problem.
I accidentally found out that Internet Explorer was guilty that my Battle.net launcher wouldn’t start. By some peculiar coincidence, it was set to “work offline” – no idea how, I never use Internet Explorer – and as soon as I returned the Internet Explorer to “work online”, the problem with the Launcher was gone.
I have no idea to which OS or Battle.net launcher versions this might be tied to, but please try this simple solution before reinstalling all of your Blizzard games… Or the operating system itself!