Console Error! when I double click the Launch icon. Google shows this problem happened before. What should I do, re-install and try it again? This one is 3GB.

There must've been a downloading error. I attempted to uninstall Banner Saga but my computer couldn't find the exe file used to uninstall the game. I went through and deleted all Banner Saga files off my computer and now I'm downloading the whole thing once again. Crossin' my fingers.

Reinstalled and ready to go. I press "PLAY" button on the GOG 1.2.64 window and the "console error!" message pops up again. Maybe I will request a refund and try to find another tactical RPG to play. There isn't much selection for tactics games in the RPG section. Oh well.
I pressed "MORE \/" then "Manage installation >" then "Verify / Repair" on the GOG Galaxy 1.2.64 window and downloaded whatever updates there were. "Console Error!" still pops up. Pressed "Uninstall" and this time it properly uninstalled. Going to check out some other games. Banner Saga looks like a popular tactics RPG, sad that I can't play it.

I thought it could be my flash player because the game window looks like it operates on flash. Double checked all my flash software and adjusted them but still no go.

You should try and contact gog support they might be able to help you with the problem.

DIdn't help

Step 1 : Go to The Banner Saga\win32\redist\vcredist\2015
Install vc_redist.x86 or vc_redist.x64
If you have an error, read it, it may be that you have already a version of VC

Step 2 : Go to The Banner Saga\win32 Right-Clic on The Banner Saga.exe
Go to compatibility and then Check the box "Run as administrator"
Apply

Step 3 Launch the Game

Thank you very much, I struggled with this problem for 5 hours, I was just freaking out, I had fits of anger, solid rude words, but as soon as I dropped my hands, your post caught my eye. All my words cannot describe my gratitude to you. Bless you Bigglaerer, you saved my life. Sorry, i used translater, so it's can was written stupidly