You're welcome. I'm glad to hear it's working now. Thanks for taking the time to post an update with your findings.
cele93:
-copy the folderC:\Program Files (x86)\Arduino\hardwarefrom the non-corporate pc to the corporate one
This step is most likely not necessary, since that folder is only supposed to contain the Arduino AVR Boards platform that comes bundled with the Arduino IDE installation. Some people do manually install boards platforms into that folder, in which case you could copy it over. Boards Manager never touches that folder.
The better place to do manual boards platform installations is {sketchbook folder}/hardware, where {sketchbook folder} is configured in the Arduino IDE's File > Preferences > Sketchbook location option. So if you want to be really complete in transferring every possible platform installation location, you should also do {sketchbook folder}/hardware. If you haven't done any manual installations then that folder won't exist.
cele93:
Please correct any mistakes if I wrote something wrong
It is a good workaround. It's best to get Boards Manager working, since it's a very convenient method for installing and updating boards platforms, but in a locked down network situation, your workaround may be the best option.