This might not have to be an issue with the hub itself, but I've encountered this a few times already and now again. I tried to download the editor twice and it gave me an error message that it failed and the file might be corrupt or something along those lines. Many installers have sanity checks in place, yet I've rarely experienced this with other software while it happens pretty often with Unity. Could it be an error in your download/write to disk code, maybe? I can't reproduce this at will, so it might not be as useful - just a heads up for you guys. Also, the hub is pretty nice. I'd have a minor suggestion, though: if the installation fails (as it did in my case), remember the previously selected components so that I don't have to do this again. That'd be really convenient.