I have a fresh install of Mojave and of Mindstorms Ev3 home edition. It seems to work fine but then randomly all the information disappears from the blocks at the bottom of the screen, and sometimes in the program too. See screenshot. This problem persists until I restart the software. Any tips?

Note: easy way to reproduce this problem is clicking on a block link from the documentation area, like the 'Loop' block in the screenshot below. It seems to cause the corruption every time.

enter image description here

  • 2
    It looks like you aren't the only one with this problem: facebook.com/groups/legomindstorms/permalink/1208245162657041 Unfortunately, no confirmed solutions at this point in time. Are there any error messages in Console related to the EV3 app? Commented Oct 5, 2018 at 16:38
  • @DavidLechner lego got back to me with a fix. See answer. Good customer support!
    – Peter
    Commented Oct 8, 2018 at 16:24
  • For what it's worth, I'm having a similar problem with the EV3 Educational version. After I updated to Mojave the EV3 software wouldn't run at all. I've found the Mono hint some other place and tried downloading and installing it. I can run the EV3 software now but EVERY time I do, I get blank programming blocks. I've contacted Lego tech support and they're researching and will get back with me. Commented Nov 27, 2018 at 15:00

3 Answers 3


I contacted Lego support and they got back to me with a fix, which worked great. It also has greatly improved the performance of the application.

For this issue fix, please install Mono for Mac OS found at the link below:


and choose Mono 5.10.1

  • What does installing mono do to fix the problem? Reading the mono page, it installs support for Microsoft .Net apps. Would I then install the Windows version of Mindstorms?
    – efreed
    Commented Jan 29, 2019 at 4:14

I've installed silverlight as mentioned from this page:


experienced the same problem.

Updating Silverlight to the most current version 5.1.41212.0 solved it !

Now the Lego Mindstorm EV3 Software works fine.


I had this same issue after a Mac OS upgrade to Mojave. (with Lego Mindstorms EV3 Home Edition)

What fixed it for me was to download the latest installer from lego.com and run the installer again.

It doesn't make sense because before I did this, I went to "Check For Updates" in Mindstorms and it says there was none. But something clearly changed, because before the reinstall, there was a non-intuitive little tab with the EV3 logo on it on the top left (as seen in the original question's screenshot) and after the reinstall, that tab has "Lobby" labeled next to the icon.

Updating silverlight didn't help. I did not try the mono suggestion.

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