Windows 7 customers that connect a drive larger than 2.2 Terabytes through an eSATA port can experience some issues; "An eSATA drive larger than 2.2TB may appear to be smaller than it's actual size when plugged in to an eSATA port. The disk may appear as expected size if the drive is previously formatted using a different eSATA controller, USB, or 1394. In this scenario some read or write attempts may fail," Microsoft warned.
'This can happen if the controller driver underreports total number of sectors on the disk. Drives with more than 32-bits worth of sectors are reported using 32-bits, causing an artificially low disk size to be computed. SATA specification allows for up to 48-bits worth of sectors. Windows uses READ CAPACITY (10) and READ CAPACITY (16) to identify number of sectors on disk up to 64-bits worth, as described here," explained MS in KB981627.
Customers experiencing this problem should contact their SATA controller vendor for updated drivers.