I can't read this floppy in one Mac, but it works just fine in
my other Mac.There are several possible culprits, the most likely being the
disk format. The earliest Macs used single-sided 400k floppies, which
some of the Power Macs cannot read. In 1986 Apple introduced
double-sided 800k floppies on the Plus. Previous Macs will not work
properly with double-sided disks.
A few years later Apple started shipping high-density floppies
(called FDHD or SuperDrives). These 1.4 MB disks cannot be read in
any Mac without a high-density drive. If you're trying to read 1.4 MB
disk in a Plus, unupgraded
Mac II, or early SE,
that could be the problem.
Another possibility is that you've managed to format a
high-density (HD) floppy in an 800k drive. I've seen this fairly
ofter. Macs recognize HD disks by the second square cutout on the
disk. Since pre-HD Macs don't look for that, they are perfectly
content to format these disks to 800k. To make these disks readable
in a newer Mac, put opaque tape or a label over the HD square.
Still another possibility is that you are using IBM formatted
disks. Macs with HD drives can read and write IBM floppies,
but only if PC Exchange, DOS Mounter, or a similar program is
installed. But that's only in Macs with HD floppies - you can't use
IBM format disks in 800k drives.
With modern Mac lacking an internal floppy drive, reading Mac and
PC high density drives isn't a problem, so long as you have a USB
floppy drive. However, none of the USB floppy drives will read Mac
800k floppies.
Finally, there's the possibility that one of your drives is out of
alignment or needs to have its heads cleaned. Cleaning is usually
simple: insert a cleaning disk. And sometimes blow out the dust
bunnies with compressed air - it's amazing how much dust can
accumulate inside a floppy drive.
The older a drive and the more heavily used, the more likely
misalignment. The only solution is to replace the drive, which is
typically about $60 and usually an easy installation. (Big exception:
compact Macs such as the Plus, SE, and Classic.) 
Further Reading
Troubleshooting Your Mac Articles
[an error occurred while processing this directive]
- <back to Troubleshooting
Your Mac>
Low End Mac Reader Specials
Memory To Go Special: MacPro 8 Core Memory 4GB kit $192 / 2GB kit $109. MacBook Pro / MacMini / iMac Intel Core2 DUO 2GB $44 1GB $23--Free shipping available.
Download Typestyler, still the Ultimate Styling Tool for Internet, Print and Video
Graphics. Works great in Classic with a Native OS X Version on the way. Free
Tryout: www.typestyler.com
LA Computer Company: LA Computer Company: Specials on AppleCare, Apple Displays, MacBooks, iMac's, MacBook Pros, Laptop and iPod accessories and more. Apple A/C Adapters for laptops starting at $25.00 Call 1-800-941-7654 or Click Here.
Other World Computing: OWC Mercury On-The-Go FW400/800/USB2/eSATA Solutions: High Performance A/V Rated, **Bus Powered** Hard Disk Storage - **Now 40GB and up to ***250GB*** in the palm of your hand. Macworld Magazine Editor's Choice - from $87.99!
Mac users can finally play Party Poker for Mac. Not only that, they can also learn how to play PokerStars for Mac.
Laptop Hardware Provided by TechRestore - Overnight Mac & iPod Repairs.
Compare products like desktop computers, laptops, and LCD TVs side by side! All the information and reviews to make the best purchasing decision for a new cell phone GPS products or MP3 players. The Ciao network makes searching products easy for you.
NEW MacPro Memory 800Mhz With Apple Spec Heat Sink 2GB Kit $104 / 4GB Kit $184 / 8GB Kit $362 Click to Maximize your Macs...
