# Cannot open because another application already has it open?  But it's not open!



## momofpreston (Apr 20, 2011)

Hi Everyone,

Okay, so when I try to open my LR...(LR3.3 64, on a PC) It will not open, and comes up with this message: The Lightroom catalog named "Lightroom 3 catalog" cannot be opened because another application already had it opened.

I have tried restarting, I have tried reinstalling on "repair", I have tried looking every where I know to look for an open application, and I can't find anything!  HELP!   I'm afraid of loosing everything in there! :(


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## Jim Wilde (Apr 20, 2011)

Hi, welcome to the forum.

Make sure that Lightroom is closed down, then use Windows Explorer to browse to the folder that contains the "Lightroom 3 Catalog.lrcat" file, and see if there is another file alongside it called "Lightroom 3 Catalog.lrcat.*lock*". If this 'lock' file is there, and you are sure that Lightroom is not active, then delete the lock file (*but not of course the proper catalog file which ends in .lrcat)*. The try restarting Lightroom.

If there isn't a lock file present, get back to us and we'll think some more....


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## momofpreston (Apr 20, 2011)

That was it!!!!  Thank you SOOOOOO much!  You just made my whole day! Gosh.... you probably just saved me from a nervous breakdown!  Thank you, thank you!!!


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## Jim Wilde (Apr 20, 2011)

Great! Glad it worked out so quickly.

For future reference, every time Lightroom starts and opens a catalog, it creates an associated 'lock' file which serves the purpose of preventing a catalog being shared with another user (as you've just found out, Lightroom will not open a catalog if a lock file is present). When you close a Lightroom session, that 'lock' file is deleted.

This works fine except when Lightroom terminates abnormally (e.g. a power failure or a system crash), and the lock file can't be deleted. So when you then try to open Lightroom.....gotcha!! So when Lightroom is active, you should see a lock file (so don't go and delete it, that would be bad news!), but when Lightroom is not active there shouldn't be a lock file. All clear?


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## Miel73 (May 6, 2011)

*LR Version:3.4Cannot open because another application already has it open? But it's n*

Hi Everyone,
 I also have this problem 
Okay, so when I try to open my LR...(LR3.4 64, on my laptop) It will not open, and comes up with this message: The Lightroom catalog named "Lightroom 3 catalog" cannot be opened because another application already had it opened.

I have tried restarting, I have tried reinstalling on "repair", I have tried looking every where I know to look for an open application, and I can't find anything! I need HELP. I do not understand your explanation going to windows explorer?? I need more HELP BETTER EXPLANATION PLEASEEEE AND THANK YOU


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## Mark Sirota (May 6, 2011)

Welcome to Lightroom Forums.

Look in the folder that contains your catalog file ("Lightroom 3 catalog.lrcat"), and see whether there's a "Lightroom 3 catalog.lrcat.lock" file there too.  If you are absolutely certain that LR is not running, delete the .lock file and you should be good to go.


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## Miel73 (May 6, 2011)

OK I am a little new to this so maybe you can give me a step by step/breakdown instructions on where to look? ...the only way I was able to find what you are telling me is by going to the start menu typing in the search area and that is the only way I found it when i went to delete it it did not work.. ..I appreciate the help but at this time your explanation is a little vague


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## Mark Sirota (May 6, 2011)

It's vague because I don't know where your catalog file lives.  Perhaps a Windows guru can tell us where it lives by default on Vista, but you could have moved it elsewhere.

If you search for "Lightroom 3 catalog.lrcat" in Windows Explorer, you should be able to find it.  Did you find a lock file alongside while Lightroom wasn't running?


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## Jim Wilde (May 6, 2011)

When you did the Start Menu>Search and it found the "lightroom 3 catalog.lrcat.lock" file, how did you try to delete it? In the search results box, simply *right-click* on the file-name, and select *delete* from the context menu that appears. That should work and you should then be able to start Lightroom again.

*N.B. Do not do this if Lightroom is already running, and UNDER NO CIRCUMSTANCES should you try to delete "lightroom 3 catalog.lrcat"!!!
*


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## Miel73 (May 6, 2011)

yes I did all that i right clicked on it and deleted it but went back on to try and open lightroom still getting that same message ...I do not get it ??? so I am not sure if it is running i do not know how to stop it from running if i am not able to open it ??


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## Miel73 (May 6, 2011)

Well I figured it out but ask me where I went and what I did lol I would not be able to tell u that but thank you again for your help/ patients will have to read up more on things like this so that I am able to get myself out of it


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## Jim Wilde (May 6, 2011)

OK, glad to hear it's fixed now. One thing I would recommend is to try to get somebody who's reasonably computer literate to show you how to the use the Windows Explorer....it really isn't that difficult and having that knowledge would be extremely useful should we get into similar difficulties again.

Enjoy!


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