Tasks needing admin password (Finder, Installer) hang with beachball for minutes Taks needing and admin password, like deleting certain files in the Finder or running an application installer, hang for minutes with a beachball. After a couple of minutes the dialog asking for an admin password appears finally. 

Once the window finally appears it also takes a minute to be usable. After I entered the password everything works just fine.

The same also happens when trying to mount a disk image with a password. It takes minutes for the password window to show up.

I can't see anything happen in Activity Monitor. CPU usage is low and RAM is plentiful. Other applications continue to run quickly.

OS X 10.10.2

MacBookPro11,3 2.8 GHz i7 16 GB RAM
In order to eliminate the User profile problem, log in as different user and check.

I would also repair the System permissions (in disk Utility) and the User permissions (the ACLs)