Get Access to all of the partitions of USB in Windows

Solution 1:

UPDATE on Windows 10 1703

Microsoft finally did away with this ridiculous limitation. Since Windows 10 1703 (“Creators Update”) you can now access all partitions on removable drives.

Original answer

Windows only supports the first partition on USB thumb drives (specifically, USB Mass Storage devices with the “Removable” bit set). There is nothing you can do about this.

Update

For the sake of demonstration, I created a USB thumb drive with the following layout using Linux:

Device     Boot   Start     End Sectors Size Id Type
/dev/sdb1          2048 2099199 2097152   1G  6 FAT16
/dev/sdb2       2099200 4196351 2097152   1G  6 FAT16
/dev/sdb3       4196352 6293503 2097152   1G  6 FAT16
/dev/sdb4       6293504 8390655 2097152   1G  6 FAT16

When plugging it in, Windows tells me to format the first partition, as expected. diskpart’s list partition yields a rather disturbing output:

Partition ###  Type              Size     Offset
-------------  ----------------  -------  -------
Partition 1    Primary           1024 MB  1024 KB
Partition 0    Primary           1024 MB  1025 MB
Partition 0    Primary           1024 MB  2049 MB
Partition 0    Primary           1024 MB  3073 MB

list volume confirms that Windows won’t ever work on those partitions:

Volume ###  Ltr  Label        Fs     Type        Size     Status     Info
----------  ---  -----------  -----  ----------  -------  ---------  --------
[...]
Volume 16    J                RAW    Removable   1024 MB  Healthy

Because if it isn’t recognized as a volume, you can’t format it or assign drive letters. It’s simply not possible.

Disk Management just spits out incorrect error messages:

When trying to format a partition except the first...

...or when trying to open the drive letter or properties dialog.

These tests were performed on Windows 8.1

Solution 2:

I think so. Using disk management, you should see 3 separate partitions Right-click the ones without disk letters and choose Change Drive Letter and Paths.

Use it to assign a drive letter. It should show up now.

Follow this steps for adding a drive letter.

Try formatting the drive as NTFS and then partitioning.