[thgil]

Hey everyone, I would really use some help!! I know this might seem like a common question, but upon hours of search I cannot find a solution.

A few things beforehand:
1) I just installed windows 7 via bootcamp
2) I have a Seagate goflex desk 1TB that I use to store files on OSX and use it as a time machine with no problem. It has two partitions.
3) I have a 2.1 intel duo core macbook

So I used my seagate HDD to store some big files that I wanted to transfer to windows 7. When I plugged the HDD in, the device was recognized by windows, but I would not access it in any way. So I went to "administrative tools" -> "disk management" to see what's going on. The HDD was there, but the contents were under one big unpartitioned block. For some reason decided to right click "format to MBR" or "GPT", not sure which one. The HDD still couldn't be accessed. But when I went back to OSX, the HDD couldn't be mounted at all. Plus the name of partition became "disk1s1". When I go back to try "format to _____" (whichever one I didn't do first), it still doesn't work on OSX or windows 7. So now I basically have a 1TB HDD full of photos that can't be accessed through windows 7 or OSX....

Someone please help!!!
Thanks a lot!

[ghporter]

Welcome to our forums. Unfortunately I have bad news-you have pretty much lost everything on the big chunk of that drive you're trying to access.

The "big unpartitioned block" on the drive was formatted for OS X. Then you told Windows to format that chunk, so it did, wiping out your files. That apparently also changed the drive's partition table, so OS X can't use it. I hope you didn't have anything irreplaceable on that drive, because you've pretty well permanently deleted it. Sorry for the bad news.

[thgil]

Hi ghporter,
Thanks for the quick reply.

I'm a complete noob, so I'm not sure if what I'm saying makes sense. But the formatting only took a few seconds, so would it still be a full format the erases everything? Also, how come I still can't access the drive on Windows?

[CharlesS]

You might be able to access the data with a recovery program like Data Rescue 3 if it hasn't been overwritten. No guarantees, though — I have no idea if DR3 is able to handle the case where the partition table is wiped out.

[P]

This may be Too Much Information, but it might help for you to understand what you did:

Every disk has one or more partitions - also known as slices. Each such partition looks like a separate HD to the operating system. The layout of the partitions on the disk is described in a map, of which there are several. APM is the old Mac one, MBR is the old Windows one, and GPT is the one both are moving to.

Each partition must also have a file system. A file system is a way for the operating system to keep track of what files are on a certain partition. Macs commonly use Mac OS Extended, also known as HFS+, and Windows uses NTFS.

I think that your external drive probably had an APM partition map, because IIRC Windows can't read those even if it has an HFS+ driver installed (Boot camp installs one). What you did was to reformat in the basic sense - to write a new partition map to the disk. You used either MBR or GPT, it doesn't really matter which. This destroyed all ideas that the disk had about what partitions were on the drive. The reason you still can't see it in Windows is that there is still no file system on it.

What you need to get your files back is either a utility that can reconstruct the partition map, or a utility that can identify individual files from the raw disk and copy them to something else. Data Rescue 3 seems to be able to do the latter, but obviously you'd need a second drive to copy them to. Ideally you'd probably want to do the former. Some googling shows links to TestDisk, which is free and claims to be able to do what you want. I have not tested it.

[CharlesS]

I would be very skeptical about trying to reconstruct a reformatted partition map. Scanning the drive and recovering files to somewhere else seems like a far safer way to go, particularly since it will not actually write changes onto the disk. You don't want to reduce what chances you do have of recovering your data.

Buy a nice large external hard disk. At least twice the size of your internal hard drive is a good way to go. Use Data Rescue to recover your files to the external, if you can, then reformat and restore the files. As a bonus, after this is all done, you can use the external drive you bought for Time Machine and never have to worry about this type of problem ever again.