Q: WiFi connection fails at startup

Change your router channel number.  Most times this works & is all you have to do.

System Preferences>Network

Click the Assist Me button.

In the next window that pops up, click the Diagnostic button & do the necessary.

Research Knowledge Base for network problems that pertain to the OS that is currently installed on your computer.   See these basic networking KB Articles:  http://support.apple.com/kb/HT1401 AirPort troubleshooting guide

http://support.apple.com/kb/HT2712 Using network locations in Mac OS X

Manually provided DNS server addresses are higher priority than DHCP's

http://support.apple.com/kb/HT1714 Solutions for connecting to the Internet, setting up a small network, and troubleshooting

============================

What to do when you can't connect to the Internet Also, run the Airport Utility app which is located inside the Utilities folder.

=====================

If using a  Linksys router, contact LinkSys Customer Support and/or post in their forums.

If using Apple's Airport, please re-post over in one of the AirPort Forums.

I have exactly the same problem. At startup the computer fails to connect to the wi-fi automatically.

If I switch off the wifi and then on again, it connects easily.

The connection is not lost if the computer stopped (stand by) instead of shutting down.

I have also tried assigning manually the DHCP, as I noticed that at startup it fails to obtain the IPV4 address automatically, but the problem remains.

I have noticed the problem after installing 10.8.3. My computer is a retina MBP 2.3 GHz

Could you solve the issue in some way?

+1

I have the same problem too on my brand new 13" Mabook Pro.

It was fine until I did an upgrade, and now people have pointed out here, I have to stop the wifi and turn it on again for the connection to establish.

Looks like a update bug.

HELP!!!!

I'm having a similar issue with my 2009 iMac (MID) running 10.8.3.  I am using a Linksys E2500 router.

On start or wake up I have to select my wifi network every time and enter the password. I check the box to remember the network but it never does. I keep getting the message that it cant find any preferred networks.

As long as the Mac stays on and doesnt restart or enter sleep mode it works just fine.

If the computer enters sleep mode it does not connect upon waking up. Again I have to select my network and enter password. I have to do this every time. 

If I turn off wifi and turn it back on it does not solve the issue. I again have to select the network as it forgets every time the wifi card is turned off.

I have tried several steps to correct the issue including deleting all preferred networks, renewing DHCP lease.

I have reset the router several times.  I cant figure this out.

Apple support refered me to Linksys support who wanted to charge me to fix the issue that they say is an Apple issue not the router.

My 2011 (Late) MacBook Pro running 10.8.3 does not have this issue. We have a HP Envy, 2 PS3's, 3 iPhones, and an iPad and all connect just fine.

Anybody having this issue? Any suggestions?

Have you tried going into Network preferences, choosing Advanced.., then removing the network and adding it back again?

That seemed to solve the problem for me.

I found a solution that has worked for me.

I entered in Utility Airport, selected my Time Capsule, then Modify, Wireless tab, Wireless options and finally selected a channel instead of leaving on automatic.

I selected channel 36 on the 5 GHz. However, do not think it is important which channel you select as long as there are no interferences.

So far so good

Yes, i also have this issue too.

Update to 10.8.4 still won't fix this issue.

I was able to fix the issue for myself. I am running OSX 10.8.4

Step 1:  Go to Applications >> Utilities >> Keychain

Step 2:  Locate System in the left menu and select it.

Step 3:  Locate your wireless newtwork in the list select and delete the entry. You will be asked to enter your system password to delete.

Step 4: Click on your wireless icon and select Turn Wireless Off then click open network preferences.

Step 5: Under your wirelss select advanced

Step 6: Delete your wireless network under Preferred Networks

Step 7: Turn wireless back on

Step 8: Connect to your wireless network and re-enter your security information.

cfreiler's instructions worked for me too. The problem also started when I did the upgrade from Apple the other day.

Thank you cfreuler!

Mark

Thank you so much.

Your solution is work for my case.