Which Library folder did you check? The one at the root level of the drive, or the one in your home folder? Neither should be that big. I have an unusually large /Library folder (16GBs) because of a lot of GarageBand loops I've acquired over the past couple of years, and my home /Users/francine/Library folder is 1.3GBs.
Try putting the folder into list view, then go to the Finder's View menu, bring up Show View Options, and click the box in front of "Calculate all sizes." Click the Size header in the window to arrange the items by size. If you click the triangle in front of a folder it will open and its contents will be displayed by size. If you are unable to find the space hog doing this, take a look at my article here:
http://www.pinkmutant.com/articles/TigerMisc.html
It has a list of other things to look at and the ultimate solution using the Terminal, if all else fails.
Francine
Francine
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