There were a number of PPC Macs (mainly 603e/603ev) released after the software that were unable to use OS 7.6 as issued, and that is not the least of the reasons why 7.6.1 exists. It contains the 'enabler', although that is not so-called. The update remains downloadable, so there is nothing lost and everything gained by having the full install CD of 7.6. OS 7.6.1 is sometimes dismissed as 'bloated', but if you remove the eminently unsuitable or uninteresting software, at or after installation, it is fast and responsive. It flies on a 50MHz IIci.

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