My main .lrcat catalog seems to be in my "Backups" folder, in the Lightroom folder in the standard location (My Pictures). It is not the "Main Catalog" file that is in the Lightroom folder. Also, my backups are not behaving as though each one is completely cumulative; when I try to delete some older backups I find that the Main Catalog has dependency on SOME older backup files. I am running Wiindows 7 Professional and Lightroom 5.6 . This is occurring on a new computer after migration--though I have observed this problem on my older computer as well (also Windows 7). Note: when closing LR I back up catalogs each time, clicking for "test integrity before backing up" and "optimize catalog after backing up". What I'm observing does not seem to be in line with what LR documentation says about how LR backups work. Would appreciate some technical help!