My photographs are gone!?

[ArmyMedic]

I opened up lightroom to import my session from this morning and it crashed and prompted me to send and error report. This has happened before and it seemed like an easy fix, but I don't remember how they did it.

It won't let me get into lightroom now with my photographs. It says something to the effect, lightroom catalog is already being used by another program, choose a different file?

I tried to choose a different file and still can't find my photographs? 

Thanks in advance for any help.

[Per Berntsen]

When Lightroom is running, there is a lock file present in the same folder as the catalog to prevent other users from accessing the catalog. The lock file is normally deleted when you close Lightroom, but if it crashes, the lock file may not be deleted.

To fix this, use the Windows file explorer/Mac finder and go to the folder that contains the catalog. This folder is usually named Lightroom or Lightroom catalog, and usually located in the Pictures or My pictures folder.

Open this folder, and delete the file that ends with .lock (for instance Lightroom catalog.lrcat.lock) Do not delete anything else.

Now launch Lightroom.