Finder
Unable to open Finder and access applications on my computer since the recent update.... HELP please!
MACBook Pro 13-inch Mid 2010-OTHER, OS X Yosemite Version 10.10.3
Resetting SMC as well as NVRAM could solve the problem
Or boot in single mode, then
Go to /Users/Your name/Library/Preferences, then delete following file and reboot could solve the problem.
com.apple.finder.plist
com.apple.sidebarlists.plist
Mac OS X: How to start up in single-user or verbose mode - Apple Support