Convert Windows 7 to ESXI 5 (P2V) fails

Hi,

I get the following error:

FAILED: The VSS snapshots cannot be stored because there is not enough space on the source volumes or because the source machine does not have any NTFS volumes. Error code: 2147754783 (0x8004231F).

I have windows 7 Pro with SSD.

Used space: 16 GB

Free space: 39.7GB

any idea how to solve this issue?

Thanks!!

Dotan.