# Lightroom cannot open catalog because another application already has it open.



## DanielK (Jul 8, 2013)

Hi Guys, 

I'm new here and very worried and desperate.

I'm using Lightroom 3.4.1 64Big on Windows 7 Ultimate.

I opened Lightroom as normal and it froze, as did everything on my computer - so I reset.

When I restarted lightroom, I recieved a prompt not allowing me to use Lightroom, saying that the catalogue was in use by another program....etc...etc

I've googled this issue, and everyone says to delete the "lock" file, however when I look into my folder, there was no lock file at all. Nothing.

So now I'm worried.

I double clicked my Lightroom Catalog 3 icon, and Lightroom opened - but there were NO folders, no photos. Nothing. 

I'm so desperate as I have done so many edits and haven't backed up for a couple of weeks....I hope someone can help me.

I've attached a screen print of what my Lightroom folder contained.


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## Jim Wilde (Jul 8, 2013)

Hi, welcome to the forum.

First question: what did you do between the first attempt to start Lightroom after the system restart (when you got the "catalog in use by another program" message), and the subsequent attempt when it DID start but with an empty catalog? Something obviously changed, but what?

Second: could you hold down the Ctrl key when starting Lightroom and you should see a "Select Catalog" screen....can you post a screenshot of that screen.

Third: could you search your computer for files ending in "lrcat", and post a screenshot of the results?


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## DanielK (Jul 8, 2013)

Hi Jim, 

Thanks for replying. When I restarted the computer, I immediately tried to open Lightroom and that's when I recieved the prompt that I couldn't open the catalog. So then I went to google to search for similar issues - and all of them said to go to : User - My Pictures - Lightroom - etc and find a .lock file and to delete it. 

When I looked in my folder (the first screen shot) there was no .lock file thus nothing to delete.

I then opened the icon that said "Lightroom 3 Catalog" and Lightroom successfully opened however had absolutely no folders or files. It's like lightroom was just installed.

I will attach the screens of what happens when I hold down the Ctrl key when starting Lightroom, and also the search results for "lrcat" files (I will post 2 screens for this as there are so many results)


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## DanielK (Jul 8, 2013)

Hi Jim, 

From my "lrcat" search results - I noticed a "lock" file for the 8th July at 7:17pm which is when i first opened lightroom.

I just deleted this 'lock' file and double clicked on Lightroom Catalog 3 - and it opened and everything is BACK!

Thank you so much. Whilst you didn't need to reply, your initial post asking me to search "lrcat" files directed me exactly which folder I needed to access.

I really am so grateful. Thank you.


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## Jim Wilde (Jul 8, 2013)

While I'm glad that everything is back, it perhaps should be clear that you have actually been using a backup catalog as your master catalog, probably for quite a while. This can often happen to the unwary as there are options in the Lightroom preferences which you use to tell Lightroom which catalog to open when you start it via normal means. One of these options (which I suspect you have got set) is "Load Most Recent Catalog".....so if you open a backup catalog for some checking purpose, then don't realise that the startup option is "load most recent", Lightroom then automatically starts with that backup catalog every time thereafter. 

Assuming the catalog that you have just opened is the correct catalog, I'd suggest a couple of things:

1. Go to Edit>Catalog Settings>General Tab and write down the exact name and location of the catalog that you are using.

2. Close Lightroom, then in Explorer open the Pictures/Lightroom folder and drag the Lightroom 3 Catalog.lrcat and the Lightroom 3 Catalog Previews.lrdata out from that folder and put them in a temporary location (to be deleted when all is sorted out), e.g. drag them to the desktop.

3. Then locate the catalog that you were using in step 1, and drag both it and the associated Previews.lrdata file up into the root of Pictures/Lightroom, i.e. replacing what was moved out in step 2.

4. Then double-click the catalog file now in its new location, and check that it opens and everything is present and correct.

5. Then go to Edit>Preferences>General Tab and change the setting under the Default Catalog section....either make it the specific catalog that you now have open, or select "prompt me when starting Lightroom". The latter is useful if you use more than one catalog, the former is the safe option if you only use one and you want to avoid the problem you just ran into.

Any questions, get back to me.

P.S. You might want to think about changing the default Explorer settings to show file extensions. I have no idea what Microsoft engineers were thinking when the elected to have "Hide file extensions" as default.


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