I put XOD install .exe on a thumb drive & asked my students to install it in class, which went fine, but on first upload to Arduino, they got an error message about unable to access a URL. I assume this was for Arduino Uno-specific data needed to do compiles. After error, upload just hung. After connecting to internet and trying to upload again, it just hangs and apparently is assuming data was downloaded, but it is not available.
Uninstalling XOD & re-installing did not resolve the issue. How do I fix their XOD install now? How do I install all required files so internet connection is not needed next time?