My adobe lightroom crashes on startup. I have tried pressing 'ctrl' on startup and testing integrity of catalog, but it won't even let me get that far. It thinks another copy of lightroom is already open. Please advise on how to fix,
Open the folder that contains your catalog and look for a file with the .lock extension. It will have the same name as your catalog except for the extension. That file be deleted, and then Lightroom should start.