[AdrianK_IT]

Does anyone know where it might be possible to get support on using SelfImage? Any experts in the UBCD4Win community? Or knowledge of links to forums where there is expertise? (There's lots of scattered info out there, but the author appears still to be under the radar, and there's no dedicated site that I can find.) I use SelfImage a lot, and (used to) think I understand it. However, I'm baffled by an instance where I cannot image only used blocks; none of the usual reasons seem to apply. If anyone uses the software, and thinks they may be able to offer advice, I'll post more details.
With thanks.

[AdrianK_IT]

Problem Solved! - or, rather, the problem wasn't what it appeared to be, and was trivial.
I have a dual boot Win Vista and Win 7 PC. Originally, Vista and 7 OSs were on separate hard disks, and I could create a used-sector only image of either OS partition from either OS. (The boot files are on the Vista partition, C:.)
I then changed the setup so that 7 was on the same disk as Vista, whereupon the SelfImage user interface implied that when imaging the Win 7 partition (mounted as D:, from either Vista or 7) unused blocks were not being skipped ('N/A').
Turns out it was skipping used blocks after all, the interface message was incorrect. The image files are the size one would expect for the amount of data being imaged and the chosen level of compression.
And, the partition is properly restored from the image, using zcat from a linux boot disk.