Apple has released a new update for Mavericks, 10.9.4 available via Software Update or via download from the Apple website
The OS X Mavericks 10.9.4 Update is recommended for all Mavericks users. It improves the stability, compatibility, and security of your Mac.
This update:
Fixes an issue that prevented some Macs from automatically connecting to known Wi-Fi networks
Improves the reliability of wake from sleep
Includes Safari 7.0.5
For detailed information about this update, please visit: http://support.apple.com/kb/HT6281
For detailed information about the security content of this update, please visit:http://support.apple.com/kb/HT1222
