Corruption of LR 3 catalog

[DThomas]

I recently added the NIK Silver EFEX Pro v2.0 as a plug-in to LR (Windows 7 Pro, 64-bit system).  After a session using this tool I closed LR.  Nest, on attempting to open LR, I received the following message: "Lightroom catalogue named "Lightroom 3 Catalog" cannot be opened as another application already has it is opened.  Quit the other copy of Lightroom before trying to launch."  I cannot find anything else open that links to the LR catalogue and have no other catalogue.  I tried reinstalling LR 3, but to no effect.  Please give me any thoughts on what is going on and what I can do to fix this?

Thanks for any help you can provide, Dave

[john beardsworth]

Look in the folder where the LR catalogue is located, and see if there is a lock file there. If so, delete it.

I assume you've restarted the PC.

John

[DThomas]

Thank you for taking the time to reply.  I looked in the folder and can find no indication of a locked file or folder.  I have rebooted my computer several times.

Dave

[Per Ofverbeck]

Thank you for taking the time to reply.  I looked in the folder and can find no indication of a locked file or folder.  I have rebooted my computer several times.

Dave

It is not a ´locked file or folder´ you´re looking for (and rebooting won´t help).

What you´re looking for is a very small (42 bytes on a Mac) file called ´Lightroom Database-3.lrcat.lock´ or similar right beside the ´Lightroom Database-3.lrcat´ file (which is HUGE; it´s the catalog itself).  While Lightroom is NOT running, erase that small ´.lock´ file, and leave everything else as is. Then try to start Lightroom again.

This kind of lock files are a very common method of flagging a database as being open.  They don´t contain any info; their mere existence or non-existence is the message. So, when Lightroom closes the correct way, it finishes the process by removing this file, and then recreates it when it opens again.

[DThomas]

This clarification is very helpful.  I've found the offending lock, removed it and LR has become a good citizen again.

[Kirk Gittings]

Great info, thanks. I'm in the same situation.