This patch alters the System File (one of the essential pieces of software your computer uses to operate) of Mac OS 7.6.1, so that it will not crash at shutdown when a RAM Disk is in use. The problem was identified on Ted Landau’s web site, MacFixit (www.macfixit.com), which by the way is an incredible resource for ALL Mac users. Alex Maluta, a reader, found a fix that worked for him, however it involved using ResEdit and finding offset codes.
System 7.6.1 and a 680x0 Macintosh computer. This includes any non-PowerMac Apple computer with a 68030 clean ROM or better. This includes the Color Classic, Color Classic II, MacIIci, MacIIvi, MacIIvx, MacIIfx, any Centris, any Quadra, any Powerbook 100 series, any Powerbook Duo (except the 2300c), any Powerbook 500 series (except those upgraded with the Newer PowerPC Upgrade), any Powerbook 190 series, and the following Performa Models: 200, 400, 405, 410, 415, 420, 430, 450, 455, 460, 461, 463, 465, 475, 478, 477, 550, 560, 565, 567, 568, 575, 577, 578, 580, 600, 630, 631, 632, 633, 634, 635, 636, 637, 638, and 640. (Also included is any LC series that has the same number as a Performa, such as a LC 580.)
If your computer has a four digit model number, such as a 6400 or 7600, the patch is most likely not necessary. If you have any clone model from any clone vendor, the patch is not very necessary either. The problem affects PowerMacs (this includes all clones) rarely, so do not patch their system file unless you have the problem.