If a drive is not being listed under Windows Explorer but is showing up in the Disk Management as a healthy volume, but with EISA configuration, Disk Management will not allow you to format/partition/initialize the volume in question.
This indicates that Windows XP is recognizing the drive as an OEM volume. The drive needs to be erased, but there are varying methods, depending on the drive type, to be used to accomplish that. The drive must be erased before it can be re-initialized and partitioned/formatted.
Here are the ways to erase a drive in this situation:
For internal ATA/IDE, SATA, and SCSI drives, please use SeaTools for DOS. It includes a zero-fill feature, and once the zero-fill has been accomplished (the quick version should be fine), you can reformat the drive using Windows Disk Management.
For OneTouch 4 drives, you may use the Maxtor Manager to erase the drive. See Document ID: 200231 for guidance.
For OneTouch, OneTouch 2, OneTouch 3, and OneTouch 3 mini drives, you may use the OneTouch Manager to erase the drive.
For all other external drives, such as:
Seagate pushbutton external
Seagate Portable, and
Maxtor Personal Storage drives,
Open a Command Window. From the command prompt, type diskpart and press enter. The diskpart prompt will open.
From the diskpart prompt, type list disk and press enter. A list of disks will appear in a text format. You will return to the diskpart prompt.
From the diskpart prompt, type select disk disknumber (for instance, if the disk containing the EISA partition is Disk 2, you would type select disk 2)and press enter. A message appears saying that the disk is selected. You will return to the diskpart prompt.
From the diskpart prompt, type clean and press enter. At this point the drive's partition and signature a removed. You will return to the diskpart prompt.
From the diskpart prompt, type exit and press enter. Type exit once more to close the Command Window.
Use the Initialize and Convert Disk Wizard...
Close the Wizard, right-click on the disk in question and select Initialize Disk from the drop-down menu.
Once the drive is initialized, continue using Disk Management to partition and format the drive.
Additional Information: For more information on the diskpart command, refer to the following Microsoft TechNet article. From this article, you will learn about other diskpart command line syntax as well as methods for converting an EISA partition to a MBR partition.
Flash Video Tutorial: EISA Partition Issues
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