The current version of the EV3 Lab software is not compatible with the upcoming update to macOS, called Catalina. LEGO is therefore introducing a brand-new EV3 app in November 2019, called LEGO® MINDSTORMS® Education EV3 Classroom. Based on the SPIKE™ app, EV3 Classroom will feature a coding language based on Scratch that LEGO is confident will unleash the full potential of EV3 in the FIRST LEGO League program. The first release of EV3 Classroom will be in US English, followed by the other 15 EV3 languages in spring 2020.
To continue to enjoy an uninterrupted EV3 experience and to avoid losing your programs, LEGO strongly recommend that you do not update to Catalina until the end of the FIRST LEGO League season in July 2020. If you have already updated to the new OS, please contact Technical Consumer Service at education.LEGO.com/en-us/support to discuss how we can help you during this transition period.
For further questions and support, we encourage you to reach out to LEGO Technical Consumer Service using the link above.