General Info

By: Mike Kimball - Revised: 2006-06-13 devin


General information about Mac OS 8.6 including requirements, installation, new features, and new software.

Hardware Requirements

Mac OS 8.6 can be installed on any Macintosh that originally shipped with a PowerPC processor that has at least 24 megabytes of physical RAM and a minimum of 32 megabytes of logical RAM (virtual memory is set to 64 megabytes by default if there is less than 64 megabytes of physical RAM installed). Also, Mac OS 8.6 can be installed in the Mac OS Compatibility environment ( in the Mac OS X Server) by way of standard install.

Mac OS 8.6 is tested and qualified by Apple to run on Apple PowerPC-based Mac OS computers. (Mac OS 8.6 is not tested or qualified by Apple for use on Mac OS-compatible computers.)


Apple now recommends updating the OS rather than doing a clean install, because they "don't always want people messing around in the System Folder anyway." Surely they mean this only for novice users. I still prefer to do a clean install for major upgrades. I began with the usual run of Disk First Aid (yes, I know that the install application does this, but I do it anyway), and then a rebuild of the directory using DiskWarrior.

I did a clean install of the system and then installed Conflict Catcher 8.0.5 to do a clean system merge. This software compares the clean install with the previous system folder (which you can specify), and then produces a list of items that will be copied to the clean install (noting if it is additional or replacement). You can deselect any items from this list that you want, and then proceed with the merge. It copied absolutely everything I needed from my previous system folder, with the exception of my hacked System file splash screen for the system startup.

Mac OS 8.6: What's new?

Here's what's new in the new OS:

New nanokernel
  • Multitasking integrated into the nanokernel.
  • Multiprocessor library can run with VM enabled.
  • Full symmetric multiprocessor capability.
  • Existing applications will run without changes.
Expanded Sherlock capabilities
  • Sherlock has improved the ability to search behind firewalls, including SOCKS and authenticated proxy servers. You can also set the number of Internet connections that you can make simultaneously in Sherlock's Preferences window.
  • The Search Internet panel is now resizable so you can easily see all available search sites. Click the new Uncheck All button to quickly deselect the selected search sites.
  • The "Find by Content" section of Sherlock now allows you to index and search PDF and HTML files. You can also index or search items with a particular label, or index an individual folder (via a new Contextual menu option).
  • Several bug fixes have also been made.
ColorSync 2.6.1 and new Monitors & Sound control panels
  • ColorSync 2.6.1: The ColorSync control panel is newly designed and provides additional file format support for JPEG and GIF. The 18 new AppleScript commands that come with ColorSync provide a complete automated solution for publishing. Additional software includes more profiles and CMMs for expanded color publishing workflow.
  • Monitors & Sound: Use Apple's monitor calibrator in Color section of the Monitors & Sound control panel to make it easier to view and customize color settings.
DVD-RAM disc support
  • Now you can use DVD-RAM disks to store information, just as you can with any hard disk, floppy disk, or other removable recordable media. Using the Universal Disk Format (UDF) 1.5 to format your DVD-RAM disc, you can share information with any computer platform that supports UDF 1.5.
  • You can also view prerecorded DVD-ROM discs, such as movie or video titles. You can also format a DVD-RAM disc using UDF to share files with PCs equipped with DVD-RAM or one of the newer (Generation 3) DVD-ROM drives.
LaserWriter 8.6.5 and Desktop Printer Utility 1.2
  • Enjoy secure printing using AppleShare IP 6.1 or later and the new LW 8.6.5 driver. LW 8.6.5 also allows you to connect USB PostScript printers to your computer.
  • In the new LW 8.6.5 print dialog box, you can create a Job/Font log to view a history of your printing jobs and fonts used. You can also choose TrueType over Type 1 fonts, and force all fonts to be downloaded to the printer.
  • The new Desktop Printer Utility 1.2 allows you to create desktop printers for PostScript printers that are connected to your computer using USB or LPR (TCP/IP).
Other new features include:
FireWire 2.0 FireWire extensions are now included in the OS. Connect any FireWire device to a FireWire-capable computer to enjoy a super high-speed transfer rate.

Game Sprockets are now included in the OS. Includes InputSprockets, NetSprockets, and SoundSprockets.

Mac OS Runtime for Java (MRJ) 2.1.1 is now included in the OS. It offers performance improvements in both speed and stability. MRJ now supports a wider selection of Java applets and applications.

AppleScript 1.3.7 has several bug fixes.

URL Access provides access to HTTP/S, FTP, and HFS through the URL schemes "http://", "https://", "ftp://", and "file://". The file URLs are provided to allow one code path for local and remote data. (formerly known as SubWoofer.)

A cool demo of this capability is in the Set Desktop to Webcam Pict script,

PlainTalk 1.5.4 with support for 44.1 Khz input sound sources, and filtering for the built-in microphone on iMac class machines.

Help Viewer 1.2, a new updated help display engine. SDK still to come, so that developers can adopt Apple Help facilities for use with their products.

ATSUI 1.1, Unicode imaging and layout Enhancements from Mac OS 8.5 include client control over memory management and memory allocation and font fallbacks.

Installer 4.5.3/ Upgrader 1.2.4, which is more Appearance savvy, now supports volumes greater than 20GB (2275099), supports extended Finder information, and contains miscellaneous bug fixes.

Unicode Utilities work with international text to sort and collate without translating to the Mac OS character set and back.

Added locale support as a way of storing information associated with cultural conventions such as calendars, date and time formats, number and currency formats, text sorting orders, etc.

The "full" version of Mac OS 8.6

The discrepancy between what Apple says is included in Mac OS 8.6 and what you get with the Mac OS 8.6 Update is resolved: Apple's statement of what comes with Mac OS 8.6 refers to what is on the Mac OS 8.6 (full install) CD. The CD includes several components (in the CD Extras folder, etc.) not included in the Update file. The CD also lets you do a clean install of Mac OS 8.6 (which you cannot do with the Update).

You can still download these "extra" files (or, in a couple of cases, perhaps even newer versions of these files than are included on the CD) from Apple's web site. Some of these files have been just released. Others have already been out for some time. As listed on the Mac OS 8.6 Update page (link dead), these files include: (all links dead)
  • MRJ 2.1.2
  • ColorSync 2.6.1
  • ARA Client Only 3.1.3
  • English Speech Recognition 1.5.4
  • OT Extras 2.0.3
  • AppleScript Extras 1.1
  • Disk Copy 6.3.3
  • iMac Firmware Update 1.0

Mac OS 8.6 and AppleScript: Installer may cause files to vanish

Several readers note that the Mac OS 8.6 Update installs an AppleScript folder that only contains an About AppleScript file. Apparently, this folder can replace your preexisting AppleScript folder, leaving you without any copy of the Script Editor or Automated Tasks folder on your drive.

By the way, the About AppleScript document refers to version 1.3.6, but it is actually 1.3.7 that gets installed.

Some indications suggest a more benign explanation. If you install Mac OS 8.6 Update to a volume where the AppleScript folder does not exist, it will create this new empty (except for the About file) folder. But, according to some readers, if the folder is already there, existing files should not be deleted.

Mac OS 8.6 Technote posted

A Mac OS 8.6 Technote is now online. (Thanks, Barry Nathan.) Here are a couple of interesting tidbits:

Startup Disk 7.7.4
On computers capable of booting from a network, the Startup Disk control panel now displays a "Network Disk" icon that a user can select in order to boot from the network.

The Startup Disk control panel will also display a "Local Disk" icon on computers that have been net booted. This allows a machine that has been booted from the network to be booted from the internal drive even when all of the internal drives have been "hidden" via the NetBoot Drive Unmounter extension (which a network administrator may have done for all net booted computers). Choosing this item actually sets the boot device to the empty (default) string, which results in booting from the internal hard drive if one is installed and contains a blessed system folder.
Text Encoding Converter 1.4.3 is now present in the System file. The extension is no longer required in the Extensions folder for the system to boot correctly.
[This is also stated in TIL article #60230. However, this may be in error. Anthony Adachi removed it and was then unable to successfully restart. A posting on Apple's Tech Exchange confirms that the TIL and Technote are wrong: John Phelps writes: "The article is will be updated."

Mac OS 8.6 does install Text Encoding Converter 1.4.3. It is clearly there on my Mac.

Marc Sheftel says that if you delete TEC, you will get a warning about the Mac not having a bootable System Folder, but it will start up successfully none-the-less.]
Finder 8.6 has following changes and corrections:
A problem on some PowerBooks where icons in the main drive window would not be drawn when it was opened after the main drive was spun down has been corrected.

A problem that could occur when copying a number of files from a Sherlock window to a folder containing some of the files being copied has been corrected. In these cases, Sherlock would ask if the duplicate items are to be replaced. If the user responded "yes", then Sherlock would proceed to delete them before the copy (and the copy would fail since some of the source items were deleted).

A problem where a crash could occur in the Finder when an attempt was made to use an alias file referring to an object on a volume that had been unmounted since the last time the alias was used has been corrected.
AppleScript 1.3.7 has a zillion fixes listed, including:
A memory leak that could occur while scripts are being compiled has been removed.

A 60-second timeout for error notifications in Folder Actions has been added.
Disk Copy 6.3.3 adds support for the Imation SuperDisk drive.

LaserWriter 8.6.5 Technotes

Apple has two new Technotes that cover LaserWriter driver 8.6.5 (included in Mac OS 8.6):
  • Introducing the LaserWriter 8 Driver Version 8.6.5 (#1165)
  • LaserWriter 8.6.5 Job Log Format (#1166).

Apple Menu item glitch fixed in Mac OS 8.6

Shiro Wilde notes that the Mac OS 8.6 Technote states: "In Mac OS 8.5, calling DeleteMenuItem for one of the first 31 menu items in a menu that has more than 31 items would damage the enable state for the menu item moved to the 31st position. Similarly, calling InsertMenuItem to insert items before position 32 in a menu that has 31 or more items would damage the enable state for the menu item moved to the 32nd position. These problems have been corrected."
This appears to explain a problem Shiro had where item 31 in his menu would be dimmed. Indeed, after he installed Mac OS 8.6, the problem vanished.

Open Transport 2.0.3: significant bugs fixed; problems still noted

Apple says that Open Transport 2.0.3 has been qualified with Mac OS 8.6 only. Using Open Transport 2.0.3 with any other version of the Mac OS may result in anomalous behavior.

The biggest news in OT 2.0.3 is that this version fixes two long-standing significant bugs:

DHCP fixes Several DHCP bugs (perhaps most noted for causing problems with Road Runner) have been fixed. In particular:
Open Transport's implementation of the Dynamic Host Configuration Protocol (DHCP) has been improved to support Client Identification and retention of the lease on a given IP address across reboots.

When using the new DHCP Client ID feature, the Client ID is entered into a new field in the TCP/IP control panel.

DHCP now sends out a decline packet when detecting a duplicate IP address.

A bug was fixed which could cause a computer to hang when acquiring a DHCP lease.

Problems with DHCP and some brands of cable modems have been fixed.
Road Runner still not running? Several readers have reported to MacFixIt as well as to postings on the Mac OS 8.6 Forum, that Road Runner DHCP problems still exist after updating to Mac OS 8.6.
Regarding this matter, Bob O'Shaughnessy notes that the new OT Extras 2.0.3 software (link dead) includes a control panel called TCP/IP Options. It allows you to select "Don't Retain DHCP Lease on Shutdown" - which seems to be designed to address the Road Runner and DHCP problem. However, it did not fix the problem for him.

Bob O'Shaughnessy reports that his problems with Road Runner vanished a few days after updating to Mac OS 8.6. He queries: "I'm wondering if this has to do with the fact that Road Runner DHCP leases are for three days, and my lease has since recycled, and I've received a new IP address."
TCP/IP Options Control Panel Bug OS 8.6 Apple TIL article #58375 (link dead) explains that the new TCP/IP Options Control Panel does not retain the "Don't retain DHCP lease on shutdown" setting. Several work-arounds are offered. The simplest is to "Trash the TCP/IP Preferences in the Preferences folder."

Don't retain DHCP lease on Shutdown" checkbox in the TCP/IP Options control panel Apple TIL article #30994 (link dead) includes a detailed explanation of this TCP/IP option. If you check the box for "Don't retain DHCP lease on Shutdown" you are "telling the client Macintosh to always release the IP address when the Mac is either shutdown or restarted." This makes the IP address available to another machine in a networked environment. Apple cross references other TIL articles which address related issues such as where the TCP/IP Options control panel that will not allow you do de-select this option once it is turned on.

AppleTalk bug fixed The AppleTalk control strip can now be used to turn AppleTalk on and off (however the Chooser option still may not work as expected):
To make AppleTalk active or inactive, use the AppleTalk control panel or the AppleTalk control strip. Using the Chooser to make AppleTalk inactive may not completely deactivate AppleTalk.
AppleScript support Open Transport 2.0 now supports AppleScript.