Still having the same issue here, I've never installed league on a mac before but it seemed so simple?
It tries to update the client first to the new client we know now. But every minute or so it gives me the same error message you guys have gotten as well. At first I could keep 'retrying' and it would progress, albeit painfully slow. and eventually the retry started from the beginning again. (It was 0% the whole time :/ but could see files being scanned go up in number)
Ive tried deleting the dmg and re-downloading that and reinstalling, but the same issue keeps happening.
If it really is an issue on riots end, I hope they fix it soon. I'd love to play on my macbook and be able to take it with me when I go to friends places :/
Anyway here are my macs details and whatnot for any techies that see this.
Macbook Pro 2010
2.4 GHz Intel Core 2 Duo
Running Version 10.12.6
I have also tried running hextech repair tool to see if I can locate any issues but it always gets stuck at Gathering logs > Copying R3D Logs...
PS. rip mac users. I feel your pain now.