If MultiFinder is not running, this occurs as soon as an application launches. The Trash (known as the 'Wastebasket' in the British-English version) empties when the Finder terminates. System 6's version of the HFS file system also has a volume size limit it supports up to 2 gigabytes (GB) and 65,536 files on any one volume. These limitations were removed in System 7. System 6 supports 24 bits of addressable RAM (random access memory), which allows for a maximum of 8 megabytes of RAM, with no provision for virtual memory. The icon in the upper right-hand corner of the menu bar simply shows the open application and is not a menu. System 6's Apple menu cannot be used to launch applications.

In comparison to the NeXTSTEP operating system of the time, System 6 does not make much use of sound, and its user interface is limited in file management and window displays.

It was licensed to Apple and Radius Inc by its programmer, Andy Hertzfeld. System 6 includes QuickerGraf (originally QuickerDraw), system software used to accelerate the drawing of color images on the Macintosh II. New software drivers allow the ImageWriter LQ to be used on AppleTalk local area networks and supports the use of tabloid or B-size paper (11 in × 17 in or 280 mm × 430 mm). System 6 includes support for the Apple ImageWriter LQ and PostScript laser printers. With MultiFinder, the Finder does not quit to free resources, and the system behaves as in the still-familiar multitasking fashion, with the desktop and other applications' windows in the background. Systems 5 and 6 have MultiFinder instead, which is much more mature and widely used in System 6. Not many programs and features function correctly with Switcher, and it does not share the screen between applications simultaneously. It was not integrated, and was only sold separately by Apple. Macintosh gained cooperative multitasking in March 1985 with Andy Hertzfeld's Switcher, which can switch between multiple full-screen applications. MacroMaker is not compatible with System 7, in which it is succeeded by AppleScript. It records the start and end locations of mouse movements, but does not track the precise path of a movement or support pauses. The pre-recorded clicks miss buttons if the buttons had moved since the recording, or if they failed to appear upon playback. As MacroMaker records only the locations of mouse-clicks inside windows and not what is being clicked on or exactly when, it can not be used to automate actions in more sophisticated programs. MacroMaker was criticized for its lack of features when compared to Microsoft's AutoMac III, which was already available commercially. It records mouse and keyboard input as macros, and has a unique user interface intended to look and act like a tape recorder. The MacroMaker utility was introduced in System 6.

Max 6 software