If you open the Disk Utility application on your Mac with the disk connected, you should be able to see it in the list of disks on the left hand column of the Disk Utility window. If you click on the the partition (i.e. The name you see in your file tree when the disk mounts under OS X) what do you see for the Format at the bottom of the window? If it is Mac OS Extended or a something similar then your disk is using the HFS+ file system, which is the default for OS X. This file system type is not natively supported by Windows, which is why the disk will not mount when you plug it into your laptop.

You have a couple of options: • Reformat the disk to FAT32, which () is the lowest common denominator in file systems between OS X and Windows. In addition to limitation to file sizes. Depends on the filesystem type and partitioning scheme whether it'll work on both. If the hard drive were formatted for HFS it would not show up on the Windows Computer. If the Partition Scheme were Apple Partition Map, it would also not show up. For maximum compatibility, back up everything from the external hard drive onto your Mac. Open Disk Utility, select the external hard drive and go to Partition.

Under Volume Scheme, choose 1 Partition, then click Options. Choose Master Boot Record. Then choose MSDOS under the Format menu. Then click Apply. Your hard drive should work on either computer at that point, as well as others you may try to use it on. If you want something that both machines / OSes can read a write, and that can act as an emergency boot drive for either machine, do this: • Reformat the drive, using the GUID Partition Table (GPT) as the low-level partition table format. Avoid Master Boot Record, which Intel Macs can't boot from.

Also avoid Apple Partition Map, which Windows machines would have no clue about. Macro with toolset autocad for mac. • Give the drive one HFS+J (Mac OS Extended, Journaled) partition large enough to install Mac OS X onto (10GB+). This volume format accommodates Mac OS X and Mac files the best.

Connect the Seagate external “for Mac” drive to the Windows computer. The drive must be connected to the computer during installation or the install will not complete.

• Give the drive one FAT32 (MS-DOS) partition, which both Mac OS X and Windows can read and write. This is a good place to put files that you want both Mac and Windows to have read/write access to.

The FAT volume format is showing its age, but a huge variety of OSes know how to work with it. • If you want the drive to have a volume that's more optimal for Windows than FAT, give it an NTFS partition as well. This would be a good volume to install Windows onto, but beware that Mac OS X only has read-only support for NTFS built-in. If you want your Mac to be able to write to this partition, you'll need third-party software to enable this on Mac OS X.