How To: Handle Virtual Memory Errors

A reader asks: What can I do about low virtual memory?

Virtual memory is a lot like what it sounds: It's auxiliary storage that resides on your hard disk, and your OS uses it when your RAM gets too full.

Virtual memory, because it requires access to magnetic storage, is slow. It can often be buggy, too, and crashes become more likely as virtual memory begins to be used. If you're actually filling up your virtual memory space, you've got problems. Here's how I recommend dealing with it.

• First, add RAM if you can. The best way to avoid using too much virtual memory is to use none at all. Adding RAM will speed up your system and keep virtual memory usage at a minimum.
• Increase the size of the paging file. The paging file is the name of the file that Windows uses for virtual memory. If you're overflowing your paging file, making it bigger can help. Click Control Panel > System > Advanced. Under Performance, click Settings. Click Advanced again, then click Change. You'll see two numbers that you can change (Initial size and Maximum size). Double them both. You can experiment with these figures until you no longer get virtual memory error messages.
• Clean up your hard drive. You may be getting error messages because your hard drive is getting full. Clean it up by running Disk Cleanup (Start > All Programs > Accessories > System Tools), then run Disk Defragmenter (directly below Disk Cleanup in the same menu).
• Reboot. The longer your system runs, the more cluttered the memory space gets, both RAM and virtual. Rebooting your system frequently clears this out and lets you start fresh. I wouldn't go more than three or four days without a reboot, and even that's a stretch. 

For more on how virtual memory works, Howstuffworks has an excellent technical primer.