I'm planning on selling my Centris 650 and to do that, I want to put a fresh install of System 7 on there. However when I put in the Install disk it tells me:

This startup disk will not work on this Macintosh model. Use the latest Installer to update this disk for this model. (System 7.1 does not work on this model; you need a newer version that does.)

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However System 7.1 is installed on there now so I don't see how it could say that when it currently is running the exact version on the hard drive. What can I do to remedy this?