Soluition to "Minecraft Story Mode Failed to start (Error 51)"
Minecraft: Story Mode has just become available on Steam. If you are encountering launch or download issues, you may be missing the complete package for the game. To resolve this, please open your Steam Library, right-click on Minecraft: Story Mode in your games list, then select Delete Local Content in the drop-down menu to uninstall the game. After it has uninstalled, please wait 30 minutes, then try reinstalling the game again. You should then receive the complete file package for the game.
Please note that this error is a Steam-related error that may occur if there are other programs interfering with Steam. To see other possible solutions if the issue persists, please read this Steam Support article: https://support.steampowered.com/kb_article.php?ref=2235-YXVB-8261
i clicked on the steam link and found that my security program was blocking it. (f-secure) check the list and see if something is blocking yours