When you open the Launcher, try to hit 'options', and then 'reset game preferences'; BEFORE the error window appears.
May The Force Be With you.
I've done all of these things and all have failed me. </3
The corrupted file will continually reappear after the launcher looks for updates of course, resetting game preferences didn't work, disabling Peer to Peer didn't work, deleting and re-installing it all didn't work. Ran as admin and as myself in all situations, didn't work.
Got to around 50-60% or so, then I got an error saying:
ERROR: The File "C:\Program Files (x86)\Diablo III\Updates\d3-0-9558-Win-Final.MPQ" appears to be corrupt. You may need to download this file again.
The installer then closed down. I get this same error message every time I try to start it up again.
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