Hi Paul.
First - The Data partition is (HPFS/NTFS)
I carried out your 'Simulated' boot instruction and the 'Invisible' so called 'Data' partition was clearly visible in the 'Work with Partitions' MBR screen as was the O/S partition and BootIt EMBRM.
I have accessed Disk Management in both O/S partitions and the missing Data partition is designated as D: and is deemed to be a Healthy NTFS Primary partition - this is an improvement on the situation at the outset (see previous post) before I deleted the drive and copied and pasted the original copy. At that point the partition was 'Unallocated.
I have read the
http://www.terabyteunlimited.com/kb/article.php?id=575 link and It doesn't appear to relate to my situation as described above? I have also disabled the fast start up in Windows 8 but It has not made any difference to the missing partition.
I have just upgraded to Image for Windows 2.88 and loaded it on to one of the partitions and the missing Data partition is visible within the program. - if that helps?
I hope this information helps to narrow down the problem.
Many thanks,
Ger