Some users like me have been plagued with a problem sometime since the release of OS X 10.9 last fall: Our Macs won't wake from sleep and reconnect to the local Wi-Fi network. Apple says the problem is fixed in OS X 10.9.4. Has it been fixed for you?OS X 10.9.4 has been in testing for weeks, first available to registered Apple developers and more recently to customers who enrolled in the company's program, which provides pre-release software to a limited number of Mac users.On Monday Apple for the general public. According to the release notes, the update 'fixes an issue that prevented some Macs from automatically connecting to known Wi-Fi networks' and 'improves the reliability of waking from sleep.'
First of all, it depends on how long it slept. After a certain time frame, more processes are frozen for the system to save energy. I believe, though, the main culprit for this is a specific setting in System Preferences/Energy Saver. Disable “Wak.