# Unexpected error opening catalog



## Morris (Aug 28, 2013)

I have not been able to open Lightroom 4, trying to use three different catalogues. Each time I get the error message "The catalog could not be opened due to an unexpected error." I have tried opening the program pressing the Control key (Windows 7), which did not seem to make any difference. I have deleted the one catalog listed with "LOCK" at the end. Is my next move to delete and reload the program?; I hate to loose all the work which I have already done.


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## Denis de Gannes (Aug 28, 2013)

Double click the actual Catalog file the one ending with .lrcat (LRCAT) extension, this should launch Lightroom and open the selected catalog.


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## clee01l (Aug 28, 2013)

Presuming that all three catalogs are not corrupt, you probably have a problem with setting in your Preferences file  This could be related to a plugin.  Use the link below to find and rename your preferences file.
http://helpx.adobe.com/lightroom/kb/preference-file-locations-lighroom-3.html

This will force LR to create a new preferences file and hopefully will resolve the problem.

If it does not resolve the problem, the other possibility is a corrupt Previews database.  Using the same link above you can find your Previews folder and Delete it. This will cause LR to rebuild your previews.


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## Morris (Aug 29, 2013)

*Opening catalog*



Denis de Gannes said:


> Double click the actual Catalog file the one ending with .lrcat (LRCAT) extension, this should launch Lightroom and open the selected catalog.



Thanks, Denis. After clicking on the catalog file, I had to reinstall lightroom. This worked, and the catalog is functioning!


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## Morris (Aug 29, 2013)

clee01l said:


> Presuming that all three catalogs are not corrupt, you probably have a problem with setting in your Preferences file This could be related to a plugin. Use the link below to find and rename your preferences file.
> http://helpx.adobe.com/lightroom/kb/preference-file-locations-lighroom-3.html
> 
> This will force LR to create a new preferences file and hopefully will resolve the problem.
> ...



I was unable to find the appropriate link on Windows 7. I did not see "AppData" after going to users (user name). But I did get the situation solved, as I described in my response to Denis.
Thank you.


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## clee01l (Aug 29, 2013)

Morris said:


> I was unable to find the appropriate link on Windows 7. I did not see "AppData" after going to users (user name). But I did get the situation solved, as I described in my response to Denis.
> Thank you.


Microsoft hides AppData as a default to protect stupid users from harming themselves. Unfortunately, the rest of us have to change that default setting before being able to access the folder. Go to the Folder Options View tab and uncheck the checkbox labeled "Hide protected operating System files from idiots"


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