my LR4 generates a "LrCatalog.log" under C:\Users\[my_name]\Documents
I post the content of the file:
04/11/2012 12:16:01 DEBUG initializing writeAccessQueue
04/11/2012 12:16:01 DEBUG immediate execution of "nil"
04/11/2012 12:16:01 DEBUG removing item about to be processed from queue: "nil"
04/11/2012 12:16:01 DEBUG executing "nil"
It seems that is some kind of debuggin log...?
I have installed the MetadataWrangler plugin and the LRmogrify plugin.
See this similar thread, where I posted details about the likely cause:
Please post any follow up comments there instead of here, including whether you're using LR 4.0 or 4.1RC. Thanks.