Introduction:
I have been playing Starcraft II arcade maps for a while in my old computer but recently bought another PC where I now play SC2 using the same account. I kept all the campaign, coop and multiplayer progress but when playing the arcade maps I had been playing for years, I found myself with no progress at all. So, how could I recover it?
Copy the Bank folder
Unlike data from the game itself (campaign, multiplayer, achievements…) arcade and custom map data is stored locally. Have you uninstalled Starcraft II in the old computer? No worries! You probably won’t have deleted the arcade data. This data is stored in \Documents\Starcraft II\Accounts<account number><another code>\Banks folder which is not deleted when uninstalling SC2. If you still have this folder you can simply copy it and replace the same folder in your destination computer, although, just in case I would copy the entire \Documents\Starcraft II folder.
Last piece of advice
Save a copy of your \Documents\Starcraft II folder just in case you want to recover or use your arcade data in another computer in the future. I was very worried the first time I installed SC2 in another computer and saw that I had lost all the progress in the arcade games, luckily the process to recover the data was simpler than I thought and I still had the Bank folder in the previous computer.
Hope this helped if you found yourself in the same situation 