Higher education programs are rapidly transitioning online in support of a broader geographic base, working professionals, and, recently, emergency contingencies such as COVID-19. The flexibility of online courses makes them attractive to adult learners; as such, there is much academic discussion about online learning for adult learners and the conversion of courses to an online format. However, most of these discussions are based on traditional higher education courses. This article discusses some of the specific practical challenges in the conversion of professional short courses for adult learners. The challenges relate to instructor isolation, student preparedness, and student support. Proposed solutions to these challenges are drawn from direct instructor experience of converting a STEM professional short course to an online format. Solutions included increasing the number of instructors and providing pre-course sessions to help resolve some technical difficulties before each class began.