I've first downloaded lightroom5 on my pc, and it opened "Lightroom-ouverture du cataloque:canapé-livre.jpg.Ircat " "Assertion failed. Then I bought the CD version and had the same answer. Then I went to chek the Picture's register, but it seems to be the right one. Then.I don't know what to do...
The catalog should not be named after a specific image. It should have a generic names such as Lightroom 5.lrcat. Then you import images into that catalog. If Lightroom will open go to the menu and create a new catalog with a name similar to what I have suggested. If Lightroom won't open then delete your existing catalog or move it to a different folder and then start Lightroom. It should give you the opportunity to create a new catalog.
Before you do that, however, take a look at File/Open Recent and see if there is another catalog available that you can switch to.
there is only one line that is opening and saying "catalogue....". And just after , there is the window "assertion failed" and it's finished. Impossible to open Lightroom.