About 1 in 5 times my network places will be missing from Finder. Not just the individual computers, but the whole network category is gone. I mess with all sorts of network and internet settings and I can't get it back. Internet connection still works fine, and the other computers on the network can still see the Mac. Restarting doesn't seem to fix it, but next time I start up several hours later or the next day it will be back. The rest of the time it works fine. Has anyone else experienced this or know how to fix it? Running Macbook OSX 10.6.1.