Mac OS X 
OS X Server (Mavericks): Xcode and Wiki web-based services take precedence over Websites
After turning on the Website or Wiki service for a site, the Xcode Service remains the default service.
Installing Apple Remote Desktop 3.3 in OS X Lion or later
You can use the steps in this article to install Apple Remote Desktop Admin when the installer reports that it requires Mac OS X v10.6.
Xserve: How to remove or install memory
Learn how to install additional memory or replace the memory in your Xserve.
iCloud: Email is delayed or returns to sender with 452 alert message
Delivery of an email message to your inbox is delayed or returned to the sender with a “452″ alert.
OS X: mach_kernel visible in the Finder
The mach_kernel file may sometimes appear visible in the Finder.
Delete photos and video synced from iTunes when you can’t access the originals
You can delete photos you synced from iTunes by syncing them with a new folder.
Get help using the Find My iPhone app
If you need help signing in, or if Find My iPhone can’t locate your device, try these steps.
