Mac OS 7.5.5

Mac OS 7.5.5, also known as System 7.5.5, is a three-disk set of system software enhancements released on September 18, 1996 that delivers improvements in stability and performance for Macs and Mac clones. This update is for all Macs running Mac OS 7.5.3, and will result in the system being updated to version 7.5.5.

Mac OS 7.5.5 included Mac OS 7.5.3 Revision 2 already, making an installation of Revision 2 unnecessary.

Mac OS 7.5.5 must be installed on Mac OS 7.5.3; System 7.5 - Mac OS 7.5.2 users needed to transit through Mac OS 7.5.3 first before arriving at Mac OS 7.5.5.

Bug fixes

 * The floppy drive is now more reliable on Macs with DOS-compatible options (e.g. the Macintosh Quadra 610 DOS Compatible)
 * System startup now more reliable for 180 MHz or faster high-performance PowerPC 604 or 604e Macs
 * Improvements in the reliability of the remote control included with the Macintosh TV and the Apple TV tuner
 * One cause of Type 11 system errors were eradicated on PowerPC Macs
 * Network made more trouble-free with the Performa 5400 and Performa 6400 series
 * Data integrity enhanced when accessing a Performa 5400 series system over the network
 * More reliable use of sound-intensive application programs for Quadra and Centris systems which have been updated with the Apple Power Macintosh Upgrade Card
 * Performance improvements mainly involve Virtual Memory -- this includes dealings with large applications and accessing SCSI devices.
 * The Universal System Folder capability has been enhanced and updated to support the Performa 5400 and Performa 6400 series. This now allows people with Mac OS 7.5.3 to create a single system folder on an external hard drive or removable media and use it to start up all Macs from the Macintosh Plus to the Power Macintosh 9500 as well as all Mac clones.

System requirements
Mac OS 7.5.5 requires Mac OS 7.5.3.

Users of Mac OS 7.5.4 may also directly upgrade to Mac OS 7.5.5.

Notes to old Macs
Mac OS 7.5.5 is the last system software release for all Macs based on the Motorola 68000 chips, as well as some other systems. These affect:

Motorola 68000 chip Macs:


 * Macintosh Plus
 * Macintosh SE
 * Macintosh SE FDHD
 * Macintosh Classic
 * Macintosh Portable
 * Macintosh PowerBook 100

Motorola 68020 chip Macs:
 * Macintosh II
 * Macintosh LC

Other non 32-bit clean Macs:


 * Macintosh IIx
 * Macintosh IIcx
 * Macintosh SE/30

The reason for ending support for these Macs is that future Mac OS releases will require a 32 bit clean-Motorola 68030, Motorola 68040, or PowerPC-based system which is 32-bit clean, which includes all other Macs.