Ok... possible source of my problem:

When I ran Canola Cleanup and re-installed I did NOT remove the 'downloads' folder on my external memory. As a result when Canola started it saw an existing folder structure - could not create a new folder (one with that name already existed) - and, perhaps, 'assumed' the disk was full.

Having now done a re-install of Canola after removing the 'downloads' folder tree I find that Canola seems happy.

Other steps I took were:
- install optional theme and Canola tuning BEFORE adding any podcast subscriptions or downloading podcasts. I did this on the suspicion that Canola might get confused if the setup changed after some of the configuration and downloads were done.

Yes, it's superstition, but that's how I run my MS Windows machine and I find it helps to stick to sequences that the developer(s) might have tried while assuming that no real-life UAT was done. ... after all, Canola should be able to figure out that the disk isn't full just because it cannot create a new directory when the correct directory already exists, right? ;-)

Hi Ho!
-P.