Thanks for this comment. I'm having the same problem, but my computer shuts off without

any prompts. I have 2GB RAM and 120 GB HD. Amy I overheating?

It is referring to system memory. Depending on the OS and architecture, Lr may be able to see part of 2GB or most of that 4GB (depending on what else is running, of course.)

Make sure you have sufficient disk space left on your boot device for virtual memory, and make sure your OS is managing the virtual memory optimally. On Windows this means not restricting the pagefile size in any way.

If you are running 64-bit (OS and architecture) you can install more memory for applications to use if you are getting out of memory exceptions.

The reason for the apparent freeze and slow downs is probably because your system was swapping virtual memory hard. You can improve things by adding more physical memory (if you can -- you are pretty much maxed out for 32-bit systems) and making sure there is sufficient space on the boot device for the paging the system needs to do. You may even have to defrag the boot device if you have been running with only a little disk space for some time.

Firefox can really eat up memory (each tab and plugin can add up.)

Assuming you are on Windows, I think there is a built in set of tools that can defrag the boot device. Check your system utilities folder in the Start menu -- it's in there somewhere. To really get the value from a defrag, make sure you empty your recycle bin and clean up any junk files. Again, you should make sure you have sufficient free disk space for the virtual memory management. A few 100MB free is probably sufficient. More is better, because modern file systems require free space for various housekeeping they do automatically.

As pointed out elsethread, some activities can really stress system resources. You can tune things to a degree, though ideally you may want to run Lr on a 64-bit system with a lot of available physical memory if you do a lot of local adjustments.

Over the course of several weeks, LR3.3 (in 64-bit mode) has been getting slower and slower. It has now reached the point of unusability. My hardware:

Macbook Pro 4,1 (early 2008, 2.4 ghz Core 2 Duo) with 4 gb RAM and a 750 gb hard drive (approx 200 gb free), running Mac OS X 10.6.6

I have multiple catalogs to keep down the catalog size, and I optimize them regularly. The catalog that I work in the most is 2.3 gb, with under 4,000 images in it, most from a Canon 5D Mark II and some from a Leaf Aptus 65 digital back.

I have gone so far as to create a new catalog with a single image in it, hoping to speed up the process of editing that image. The exported catalog is 443 mb.The image has had a lot of work done with the adjustment brush; I applied the brush to the entire image to bleach out the background, and then started erasing from the subject to restore it. Lots of relatively short strokes in that process. I have done the same thing on other images without this problem.

When opening this single-image catalog today -- no other applications were running -- it took 45 seconds to load the image after LR launched. When I clicked on the adjustment brush, it took 35 seconds to see the adjustment brush sliders. When I clicked on the navigator image to zoom in, it took 45 seconds to completely load the close-up image (the "loading" message went away 15 seconds before the jaggy image cleared up). When I clicked on the pin that I wanted to use (there are 2 pins on this  image), it took 10 seconds for the pin to become active. When I clicked on Erase to load the eraser brush, it took 10 seconds for it to switch from A to Erase. When I clicked in the navigator window to relocate to a different area of the image, it took 10 seconds to do that. When I clicked to start erasing, the spinning beach ball came up immediately. I don't know how long it was there, because I got tired of watching it after the first 60 seconds and went to do something else. When I was finally able to click & drag for about 1 inch on the zoomed-in image, nothing happened at all. I waited 5 minutes just to see if LR would finally catch up, but nothing happened. I tried again, and the first quarter-inch of the erased area showed up 5 seconds after I let go.Continuing my attempt to edit, the spinning beach ball spent a lot of time on the screen every time I clicked, whether with the brush or on a menu. I finally gave up. At least this time I wasn't forced to Force Quit the application as I have been several times lately.

This is what I've been dealing with for the past 4 days. Prior to that, LR was still functioning, but nothing happened quickly: switching from Library to Develop, opening different sections (e.g., Basic, Detail, etc., or Presets, History, etc.), dragging sliders, or anything else. I have tried restarting Lightroom, rebooting the Macbook, increasing LR's cache to 25 gb... I don't know what else to try. Other programs, such as Photoshop, are functioning normally.

Does anyone have any suggestions, before I tear out what little hair I have left?

Guy