I had an odd occurrence today. I was copying a relatively huge (50Gb), live, web site onto a USB drive using Transmit and, since it was going to take a while, I left it overnight. When I got to my desk this morning, my MacBook Pro was in an unhappy state. Even though I was copying to an external drive, Finder was complaining that my startup disk was almost full, and indeed it was. WTF?

As of this writing, I don’t know exactly why but here is the odd thing. Snow Leopard had paused all my applications, except for Finder, to allow me to recover disk space, which I tried to do. After deleting some files I recovered a couple of gigabytes and tried to “Resume” the paused apps. Nada. I did a “Force Quit” on a few, including Transmit, and eventually saw my free space shoot up (which suggests that Transmit might have been consuming VM at a prodigious rate). But I did not want to “Force Quit” my more important apps, like Mail and Parallels, so what to do with a “Resume” that does not?

With free space by the gobs, I found I could launch new apps (yay!), and launched another instance of Safari (since the other one was paused). It seems like there is no elegant way to resume paused apps, but there is a geeky way in Terminal:

kill -CONT xxx

where “xxx” is the PID of the paused process. Launched Activity Monitor, got the PIDs of the processes in question, and I was good to go. Nice orderly shutdown, and I am up and running as if nothing happened.

I remain puzzled as to why Snow Leopard does not offer something more elegant than “kill”. Thanks to superuser.com (a Stack Overflow site) for the tip.