The version of Box Tools released last month is not working with Firefox browser’s current ESR (Extended Support Release). The problem is occurring because Firefox ESR is based on a version of Firefox that is older than what Box Tools supports. Box expects that the next version of ESR, which should be released in the next month or two, should fix the issue.
In the meantime, the Box Tools plugin is working with the current (non-ESR) release of Firefox, as well as the current version of Chrome.
Box Drive is another way of opening files that are stored in Box using your computer desktop: https://www.box.com/drive
For more information about Box Tools, see: https://it.cornell.edu/news/box-tools-upgrade-released-month/20180316