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Can't install using Lion USB - get prohibitory sign (no smoking sign)

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macrumors member
Original poster
Jun 9, 2006
New York
Posted this in the Lion section too but I thought I would see if any Airheads ;) have any thoughts too...

I'm at work and thought I would throw this out for ideas...

Working on Macbook Air 13-inch Mid-2011. It had a virus and we decided just to wipe it and reinstall Lion. We work behind a firewall with a proxy so I tried to use a Lion USB installer that I often use. When booting holding option I see the installer but as soon as I select it I get the prohibitory sign (no smoking sign).

Can't use internet recovery because of the proxies (big company, no turning them off). Now trying to make a dvd installer from a lion DMG but just wondering if anyone has ideas. I've already wiped the disk, made a new partition, and done PRAM reset.

Why am I getting the prohibitory sign? Thanks.


macrumors 603
Sep 8, 2011
The installer you are using predates the what the MBA shipped with. Meaning, it's not compatible.

You would need to get a version of 10.7.1 or newer and put it on a flash drive.


macrumors member
Aug 11, 2011


Good luck with your project & maybe it is no big deal for a pro but I too have been bitten by the bug of having an install USB that was older then my hardware. And it was a real chore 4 me to have to go and produce a USB stick with the right ver. OS.

Also and I'm not trying to take up your time here but what virus? Didn't know there were any? Java related?
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