OS: Ubuntu 11.04 without Unity
Calibre Version: 0.7.44

I've been using Calibre for months with no problems. 7000+ documents with about 1084 authors and 500 series.

Suddenly today after about an hour of work, when I open the author or series list in the left window I see:

Authors
0.00-0.00 [100]
0.00-0.00 [100]
.
.
0.00-0.00 [84]

The total author count is correct. Clicking on one of these entries shows me a list of 100 authors in apparently random order.

Series is the same with a correct total count.

I did LIBRARY CHECK which came up normal

I can't find any PREFERENCES or options which affect this situation.

I un-installed and re-installed 0.7.44 from the Ubuntu repositories. No change.

Any clues?

TIA