Adding 4duino board to IDE

Before I knew which board I was buying, I installed the newest IDE 1.8.1. Today when my 4duino-24 showed up, I made it to adding the board in the board manager and already screwed something up.. I clicked 1.6.12 and installed that, then for some stupid reason clicked 1.6.10 and installed that too lol. now it won't go back to 1.6.12 and gives this error

Error downloading java.lang.RuntimeException: java.lang.Exception: Error downloading at cc.arduino.contributions.packages.ui.ContributionManagerUI.lambda$onInstallPressed$1( at Caused by: java.lang.Exception: Error downloading at at at cc.arduino.contributions.packages.ContributionInstaller.install( at cc.arduino.contributions.packages.ui.ContributionManagerUI.lambda$onInstallPressed$1( ... 1 more Caused by: Received invalid http status code from server: 416 at at at ... 4 more

I uninstalled 1.8.1, restarted and installed IDE 1.6.12 from the previous versions list but the .json URL is still in place and it still gives the same error when trying to add the board. Any help would be appreciated. Also, I'm on windows 10.

Uninstall, blow away c:/users/(your username)/AppData/Local/Arduino15 (note -appdata is hidden folder) and reinstall.

Thank you. Is 1.8.1 okay when I reinstall or does the IDE version have to match the version in the 4duino section of the board manager?

In my case, Arduino IDE 1.8.1 on Ubuntu 17.10, I just needed to delete the 4duino board files I had previously installed: 4dsystems-1.6.10.tar.bz2 4dsystems-1.6.12.tar.bz2 4dsystems-1.6.7.tar.bz2 4dsystems-1.8.1.tar.bz2

I found them in ~/.arduino15/staging/packages. I also deleted a file named ~/.arduino15/package_4dsystems_index.json.sig.tmp

(I didn't wanted to erase all my other parameters and libraries by dropping the whole ~/.arduino15 directory )