I’ve been using Lightroom extensively for the last year or so, and apart from the program requiring processing power significantly beyond the state of the art to run smoothly (though not quite as slow as Apple Aperture), I’m quite smitten by it. I’ve moved my entire photo catalog from the past eight years into it.

So you can imagine my chagrin when it one day just stopped working. “Stopped working” in this case meant that the program would, after startup, simply exit once the splash screen disappeared. No error message. No nothing. I was never given the opportunity to click anything, access any menu etc.

My attempts to rectify the problem involved:

• Swearing at the computer, accompanied by threatening gestures
• Deleting my preferences file (apparently a go-to-solution when weird things happen in Lightroom)
• Checking and rebuilding the catalog
• Upgrading from 1.4.0 to 1.4.1
• Restoring my catalog from a backup
• Pulling my hair

none of which helped me at all. I could open other (or new) catalogs, but not my main catalog containing all my 30000+ images, even when I restored the catalog from a known good backup!

After a lot of mucking around, I noticed that Lightroom apparently exited at exactly the same moment every time, while drawing a particular image on screen. I tried removing that particular image (the raw-file) from the library, but that didn’t help at all. This was when it hit me: maybe the problem was with the cached previews? Maybe that particular preview was corrupted in some way?

Scanning and rebuilding the catalog apparently only works on the .lrcat file, not the cached previews. Since they don’t have any other significance besides performance improvements, I simply deleted the entire directory. And, lo and behold, Lightroom started right up (albeit a smidgen slower, since it had to reparse all the raw files). Problem solved. Stress-induced heart attack avoided.

So, in conclusion, one more trick to try when Lightroom is misbehaving is to simply delete your cached previews. I’m not saying it will fix your problem, but since it’s unlikely that it will have any negative impact (besides a performance hit the first time the previews are rebuilt), it can be worth a try.