Accessing Mac file system on a PC

June 27, 2006 5:03 AM

How do I access a mac-formatted HD in Windows?

I run Windows XP at home, and keep all my media (music etc) on an external 500GB drive, via USB.

I lent this to someone, who proceeded to connect it to a Powerbook, and take some files off it.

When I got it back, I can't access the drive in Windows anymore; when trying to access the drive it asks me if I want to format it.

if I do this, does it wipe the data on the drive? is there an emulator that allows me to access the data and copy it somewhere else before formatting the drive?

posted by fintanc to computers & internet (13 comments total)

Mac Drive here
posted by psyward at 5:06 AM on June 27, 2006

I lent this to someone, who proceeded to connect it to a Powerbook, and take some files off it.

When I got it back, I can't access the drive in Windows anymore; when trying to access the drive it asks me if I want to format it.


Uh...this shouldn't happen. If your drive was Windows (FAT32 or NTFS) formatted, and you lent it to a friend on a Mac, he/she could have just taken files off of it and returned the drive to you untouched. The fact that when you got it back it asked you to format it leads me to think that either a) your friend formatted the drive for Mac, destroying all your data, b) the drive broke in transit.

Just by plugging it into a Mac does not "convert" a drive to HFS+ (Mac format.) Macs can read FAT32/NTFS just fine and can write to FAT32 fine.
posted by neustile at 5:34 AM on June 27, 2006

Well, tried Macdrive but it can't see the disk; in Windows it comes up as "Local disk", and I don't even get a file listing or anthing like that.

The specific error message i get is "[drive] is not accessible - the parameter is incorrect".

Any ideas past this, or am I screwed with this drive?
posted by fintanc at 6:16 AM on June 27, 2006

You need to ask your friend what they did with it exactly, for the reasons neustile gave.
posted by cillit bang at 6:40 AM on June 27, 2006

Sounds like your partition may have become corrupted.

Try the Acronis Disk Director Suite demo. It will tell you if you have a recoverable partition, buty the demo will not allow you to actually write the changes. Either way, this shouls help you to see if it CAN be recovered.
posted by zerokey at 6:42 AM on June 27, 2006

Take it to someone locally who can look at the drive to see what's there.
posted by mendel at 6:45 AM on June 27, 2006

My friend connected it to her Powerbook, grabbed some directories off it, unplugged it and gave it back to me today.

Simple as that. Looks like its a partition problem; I will try some software and see what I can recover. I wouldn't mind but I have some complete TV series on there. Ouch :-(

Thanks for all the help.
posted by fintanc at 6:53 AM on June 27, 2006

Definitely a problem on the drive or the filesystem. Did your friend properly unmount it on the Mac?

(Also, it's certain that your friend did not reformat the drive for a Mac. Doing so would have not only been silly [as the Mac can read a FAT/NTFS drive], but it would have also made it impossible for her to get any data off of the drive. So that possibility is right out).

If it is just a malformed partition header, that should be no big deal. The partition info is stored at many places on the drive, and should be easily recoverable (well, that's true on all of the filesystems I know about, but those are Linux ones...). If it's just a corrupted filesystem, that should also be fixable.

Only a hardware failure should really result in massive data loss. As a very first pass, I would run that WinXP filesystem checker thing on it. But I don't use Windows much, so I don't know if it's any good. I know it is really bone-headed about foreign filesystems [eg, filesystems that it would be trivially easy for Windows to recognize the existence of, are instead reported as free-space/corrupted. They might do other stupid things -- be careful].
posted by teece at 7:45 AM on June 27, 2006

Oo, actually, teece's initial question sounds like a potential answer—perhaps you should try plugging it back into your friend's computer, then make sure that it's unmounted properly (dragging the drive to the trash can should do it). Maybe that'll "reset" whatever plugging it into the Mac changed. I never was sure why/how an improperly unmounted drive would give you so much trouble, but it does happen—generally happens on Mac hardware, not Windows. I know people who've corrupted memory cards because they didn't unmount them properly on a Mac.
posted by limeonaire at 11:59 AM on June 27, 2006

Well, good news.

Turns out the boot sector was corrupted; I used a tool called
Tesk Disk to analyse and fix it. The whole thing took about 40 mins, very good tool indeed.

The intersting thing is that it might have been caused by connecting it to the Mac after all; I had various .trash folders and a few other things on the drive that were new.

Everything works fine now, so thanks for all the suggestions!
posted by fintanc at 12:27 PM on June 27, 2006

it might have been caused by connecting it to the Mac after all; I had various .trash folders and a few other things on the drive that were new.

OS X will automatically create various files like this in any external drive connected, regardless of the formatting -- without destroying the boot sector. Not unmounting properly could still conceivably have been the issue, though.
posted by advil at 12:51 PM on June 27, 2006

I never was sure why/how an improperly unmounted drive would give you so much trouble, but it does happen—generally happens on Mac hardware, not Windows.

On the off chance you see this in your "my comments" or something:

The problem is that in order to speed up disk access, disk writes "complete" long before the data is actually written to the disk thanks to disk cache. So the application says "write this", the operating system says "ok, written!" but it's really only written it to cache. It's only when things get quiet, the cache gets full, or the OS is explicitly told "write your cache, I'm about to remove that disk!" that bits actually show up on the disk itself.
posted by mendel at 11:58 AM on June 29, 2006 [1 favorite]

Mm, good to know. Thanks, mendel.
posted by limeonaire at 4:41 PM on July 4, 2006