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USB Mass Storage Support 1.3.5: Document and Software

This article has been archived and is no longer updated by Apple.

This article comprises a software link for USB Mass Storage Support version 1.3.5.

USB includes the notion of Class drivers, a set of software components generally delivered by Operating System vendors that are able to communicate with not just one, but many different USB devices of a particular kind. This enables any number of compliant devices to be plugged in and start working immediately without the need to install additional software. Several Class Drivers are already included in Mac OS for its computers with USB, including a hub class driver and a composite class driver. Over time, Apple expects to offer new and updated Class drivers for USB. The Mass Storage Support software represents one of these class drivers and is intended to support devices that meet the USB Mass Storage Class specification. This software consists of the two system extensions USB Mass Storage Extension and USB Mass Storage Support.


Not all devices meet the independently defined USB class specification, and so, require their own unique software to operate. Follow the vendor's directions for installing software to support their device. Use this software when the vendor recommends it or no other software is available. It is okay for both this software and a vendor's own software to be installed on the same system at the same time. When both are installed at the same time, the vendor's software will normally take precedence over the USB Mass Storage Support extensions.


Mass Storage Support 1.3.5 requires Mac OS 8.6. You do not need to install this software if you have installed Mac OS 9.

Installing USB Mass Storage Support 1.3.5

This section describes how to install USB Mass Storage Support 1.3.5. If you haven't already done so, download the USB Mass Storage Support 1.3.5 from the Apple Software Updates web site

To install USB Mass Storage Support 1.3.5, follow these steps:

  1. Open the USB Mass Storage Support installer.
  2. Choose "Easy Install" to install the USB Mass Storage Support 1.3.5 software into the extensions folder of your startup disk. USB Mass Storage Support Requires Mac OS 8.6 or later.
  3. When the install is complete the installer will prompt you to restart your computer.
  4. After your computer restarts, the USB Mass Storage software is ready for use.

Using USB Mass Storage Support 1.3.5

Plug in a compliant USB Mass Storage device to your computer's USB port to begin using it. Follow the instructions for using the device provided by its vendor.

If the message "The software needed to use the USB device 'name of the device' can not be found" appears when you plug in a USB mass storage device, the device you are using is not supported by the USB Mass Storage Support 1.3.5 software. Contact the device manufacturer to obtain the software required to operate the device.

When disconnecting a USB mass storage device from the computer, close all windows and quit all running applications that are stored on the device and drag the device's icon onto trash to dismount it from the Desktop prior to unplugging the device from the USB port or Hub.


Do not disconnect a mass storage device from the USB port while copying files to or from the device or while files or applications stored on the device are in use. DOING SO MAY RESULT IN LOSS OF DATA.

Tips and Troubleshooting

Remounting unmounted volumes

To mount or remount a USB mass storage volume on the Desktop, unplug and replug the device that contains the volume into a USB port on the computer, or into a hub attached to the computer. The volume should appear on the desktop in a few seconds. If the device uses removable media, the volume will not appear until the removable media is reinserted into the mass storage device.

Removing manual eject media

With manual eject drives, do not unplug the device from USB until the dialog states it is safe to do so.

Password Protection

USB Mass Storage Support 1.3.5 does not support Zip drive password protection. When a password protected disk is inserted while using USB Mass Storage Support, the disk cartridge will be ejected and a dialog box will appear indicating that this feature is not supported. If necessary, contact the Zip drive manufacturer to obtain software that supports this feature.

Using USB Mass Storage Support 1.3.5 with PACE Key floppy diskettes

Some commercial software vendors provide installation diskettes that are copy protected. The USB Mass Storage Support 1.3.5 software does not support reading floppy diskettes that have been secured using PACE copy protection. If necessary, contact the storage device vendor to determine if they have software available for their device that supports the PACE protection mechanism.

Version History

  • Version 1.3.5 -- Addresses potential conflicts with multiple drivers attempting to control a single device.
  • Version 1.3 -- Initial support for USB Mass Storage class devices.

Supported Devices

At the time of this document's writing (June 1999), the following devices are reported to be compliant with Mass Storage Support 1.3.5:

  • Hagiwara FlashGate SmartMedia Reader/Writer for USB
  • Imation USB SuperDisk Drive
  • Iomega USB Zip Drive
  • LaCie USB Hard Drive
  • Teac USB Floppy Drive
  • VST USB Floppy Drive
  • Yano USB Floppy Drive
  • YE-Data USB Floppy Drive

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