LR mystery - photos from a date range vanish from catalog

[PeterAit]

The oddest thing happened to my LR catalog - all the photos I took and added to the catalog in the 2nd half of April and all of May are gone, as are any folders I created during that period. The image files and folders themselves are still present on disk where they should be. What could cause this? What can I do about it?

[john beardsworth]

Not something LR would do on its own - it would require user assistance.

You could have removed them yourself, and ignored the dialog asking you to confirm it's what you intend to do. Or you could have opened a backup catalogue. Or you could have upgraded to Lr6 when it was released in April and have now opened the Lr5 catalogue. etc.