|Tip 335||Re-create the Dock from Scratch|
The following has never happened to me, but some people report it as a frequent annoyance: when dragging several files to a Dock stack, accidentally missing the target will result in all the files being added to the Dock. Because the Dock scales with size, this can make it unusable.
If deleting all the new icons seems like a little too much work, you can reset your Dock’s icons to the default state (that is, as if you’ve just booted your Mac from new) by deleting its configuration file. Open Finder, hit Shift+Command+G, and type ~/Library/Preferences. Then move the com.apple.dock.plist file to the trash. Immediately log out and back in again.