SystemUIServer process freezes indefinitely (resulting in ostensible system freeze), cannot be quit
Freezes, Apple TV sync problems and continued MacBook/MacBook Pro external display issues.
The menu bar in OS X has some customization options, plus an easy fix when the menu bar hangs and prevents the clock or other menus from being accessible.
In setting up OS X one of the convenient options is to add menu extras to the right-hand side of the menu bar, providing convenient access to system settings as well as functions provided by third-party utilities (virus scanners, activity monitors, etc). Sometimes, however, some or all of these menu extras may become nonfunctional and show the spinning color wheel when you mouse over them.
OS X supports a number of menu bar additions (known as "menu extras"), which can be convenient; however, you may run into problems where placing your mouse over the icons will give no response and may show the spinning beachball.
If your menu bar in OS X is unresponsive, the system's menu-extra handling services may be to blame.
If you are experiencing problems with a menu extra and can't seem to remove it by standard means, it may have a nonstandard implementation, which will take a couple of steps to root out and uninstall.
Root them out with Activity Monitor.
While Apple's new Notification Center has its conveniences, some may prefer not to use it, but there's no direct way to turn it off.
While there are several approaches to managing "in-use" errors in OS X, you can often make use of the Trash to temporarily store these files so as not to disturb your workflow.