[crustybaker]

Hi
Lightroom catalogs are set by date, you could try searching your main drive (c:/)
Type in the word Lightroom in the search panel and look for the date in the results that you had the problem. Light rooms catalogs have The date plus a number after the date e.g. 2015-04-20 0730. This depends on how your dates are set up on your computer m,d,y d,m,y y,m,d.

I am using widows 7,but I hope this helps

Crustybaker