Lightroom frozen after power cut

Last week we had a power outage, (lasting all of 3 seconds), but enough to shut down the Imac. Unfortunately, Lightroom was in the middle of either deleting about 9 pictures, or re-importing – I can't remember which, as I was deleting in order to re-import. Now, every time I try to launch Lightroom I get an error message: "Fatal database error at path "/Users/... ... database disk image is malformed." The options are 1) to postpone for one week, 2) to resume later or 3) to try again. None of these gets me out of the freeze. There is no option to abort. I can't therefore access any of my library and all I have is a black screen, for ever. (I'm on Mac OS Mojave 10.14.2)