Have you ever started Lightroom to be presented with an error stating Lightroom catalog named [catalogname] cannot be opened because another application already has it opened? No? You will, at some time.
This error is widespread, and thankfully, it is straightforward to fix. To fix this error: –
- Close Lightroom Classic – or the error dialogue box;
- Navigate to the folder where your Lightroom Classic catalog is kept. By default, the catalog is stored in your Pictures folder: –
- Windows: \Users\[user name]\Pictures\Lightroom
- Mac OS: /Users/[user name]/Pictures/Lightroom
- This folder will contain several files, but you are only interested in one file – [catalogname].lrcat.lock. Ensure the filename has the .lock extension at the end. Delete this file ONLY. Do NOT delete any other file;
- Restart Lightroom Classic and all is good.
Why does this Lightroom catalog cannot be opened error appear?
Lightroom Classic uses the catalog file as its database for your images. This database is essential for Lightroom to work because it contains information about your images. The information pertains to the location of your images, adjustments you have applied, metadata and a plethora of other essential facts. When Lightroom is open, it will lock the catalog file to prevent other applications from accessing and making changes to the catalog. This behaviour is not unique to Lightroom and is shared by most, if not all, applications that rely on a database.
Normally, this .lock file is automatically deleted when lightroom closes. The next time Lightroom is launched, the .lock file for the appropriate catalog is created and remains in place until Lightroom is closed. This behaviour normally happens seamlessly. However, if Lightroom is not closed properly or crashes, the .lock file is not automatically deleted and remains in place. While this .lock file is present, Lightroom cannot open with that particular catalog. It will open with another catalog that does not have a corresponding .lock file – hence the option “Choose a Different Catalog” in the error dialogue box.
This is why deleting the .lock file will allow Lightroom Classic to launch with the selected catalog.
I hope this helps and please leave your thoughts and comments below.