Q: WIFI does not reconnect after a standby

Troubleshooting Wi-Fi issues in OS X

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Same here. After wake from sleep, Wifi won't reconnect and my Mac freeze and become unresponsive. Have to hard reboot using power key to get up and running

And the same here. Have used Mavericks since release + day 2 with no wi-fi reconnect problems then about a week ago it started looking for a wi-fi after sleep.

Same here, only after MBP did a cold start. Just for the record: the WIFI connection icon displays a "!"-sign ...

Had same problem, spent 3 hours with Apple Care, reinstalled OS, finally read somewhere to turn off bluetooth, solved my problem, WiFi connects everytime after sleeping.  Works like a charm.  Hope it works for you.

Well, it may work (I did not try), but I have a bluetooth keyboard and mouse connected to my MBP.  This is not a solution for me.

I have the same problem with my MacBook Air (mid 2013) running OS X 10.9.2. Deactivating WIFI and then activitating it again after some seconds works fine but it's quite annoying and I can't belive that Apple can't find a better solution and fix that issue. I have the feelign that the issue mostly occurs when connecting to my AVM Fritz!Box 7490 with 802.11ac (5 GHz). Deactivating Bluetooth is not an option as I have a bluetooth mouse and keyboard.

Running latest version of OS and patches, Macbook Air mid 2013.

Connected USB keyboard and bluetooth mouse at work, at home I use just the macbook - no accessories

Wifi at work based on Apple airport, at home as well.

When I connect at work, standby, wake at home = fine !

Come back at work, plug in USB, monitor, power, the macbook wakes up = no wifi, no keyboard

One by one the apps 'hang', have to 'force stop' everything and reboot -> everything works fine.

This happens every time since Mavericks upgrade ...

I think to have found a slight hint what could be the reason for all these reoccurring Wifi issues.

I have had no Wifi issues for a long time now, but today I rebooted my MBP (cold) and saw the issue again. I then deleted the Wifi config from the network settings and almost instantly had the connection again?! It seems that the Wifi credentials have been synched from iCloud before? Maybe there were two identical Wifi-SSIDs conflicting (I only saw one in the list)?

Before I lost the connection every other minute, but while I'm writing this post it's stable and working without interrupts.

http://carnationsoftware.com/LastA2DPDevice_Mac_Wireless_Problem.html

Trash your Bluetooth preferences, restart your Mac.

Open Bluetooth Preferences (Apple Menu, System Preferences, Bluetooth)
Remove any audio devices that are shown in the upper section of that list.

Pair your Bluetooth Speaker or headset device and then connect and disconnect it.
Open /Library/Preferences/com.apple.Bluetooth.plist

If the LastA2DPDevice item is present, then you know you have just paired a A2DP device. You need to trash your Bluetooth preferences and restart your Mac again.

The problem is caused by an interaction with Bluetooth and specifically Bluetooth devices that use Advanced Audio Distribution Profile (A2DP) which is used to stream bluetooth audio from devices such as Bluetooth headsets and Bluetooth speakers.

The problem is caused when the Mac goes to sleep and wakes back up. It tries to connect to the A2DP device that was last used by the Mac. If that device is not powered on or is not in bluetooth range, it will keep trying to connect to that device (for an unknown amount of time). While it is looking for that Bluetooth device, the 802.11 wifi is also looking for the last wireless router or access point and fails to find it.

Why the wifi is unable to reconnect after waking from sleep is not exactly clear because wifi is a different protocol than Bluetooth. One hint is that it only seems to fail with wireless routers that run on the 2.4 Ghz band. That is the same frequency that Bluetooth uses (even though Bluetooth hops through different smaller bands within that frequency.)

I do not have the problem when at home and connected to my Airport Supreme Wireless AC router which is running on the 5 Ghz band.

To prove this, here is what I did...

1. Go to a location where you are having the sleep / wake wireless problem and take your Bluetooth speakers or Bluetooth headphones with you.

2. Now while at that location, Connect to the wireless network there.

3. Turn on the power to your Bluetooth device (speakers or headphones).

4. Turn Bluetooth on and connect to your Bluetooth device.

5. Put your Mac to sleep for 45 seconds (that is enough time for the Macbook to shut down power to Bluetooth.)

6. Wake your Mac back up and you will notice that there is no problem reconnecting back to the wireless network.

7. Now turn OFF the power to your Bluetooth device and put your Mac to sleep for 45 seconds.
You will see that your MacBook will not connect back to your wifi wireless network after it wakes from sleep.

That is because it is looking for your Bluetooth device that it cannot find.

Note that this test is only valid if you are using a Bluetooth device that uses the A2DP protocol. I did my tests with a Bose Soundlink Mini speaker.
I am connecting to a Netgear N300 Wireless Router (WNR2000)

Thanks for sharing this tip--Your solution worked well for me.

Thanks for sharing. Seems it helped me at home at least: removed BT headphones from list and removed the preferences. Will check tomorrow in the office. Thanks again.