Comment 94 for bug 1286552

The problem seems to occur after kernel updates. NetworkManager needs to be restarted ('sudo kill PIDforNetworkManager") after suspend.

uname -r
3.13.0-36-generic
apt-cache policy network-manager
network-manager:
  Installed: 0.9.8.8-0ubuntu7
  Candidate: 0.9.8.8-0ubuntu7
  Version table:
 *** 0.9.8.8-0ubuntu7 0
        500 http://archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages
        100 /var/lib/dpkg/status

*-network
       description: Wireless interface
       product: Centrino Wireless-N 1000 [Condor Peak]
       vendor: Intel Corporation

$ lsmod | grep intel
snd_intel8x0m 18830 0
snd_ac97_codec 130285 3 snd_via82xx_modem,snd_atiixp_modem,snd_intel8x0m
snd_hda_intel 56451 3
snd_hda_codec 192906 3 snd_hda_codec_hdmi,snd_hda_codec_conexant,snd_hda_intel
snd_pcm 102099 7 snd_ac97_codec,snd_hda_codec_hdmi,snd_hda_codec,snd_hda_intel,snd_via82xx_modem,snd_atiixp_modem,snd_intel8x0m
snd_page_alloc 18710 5 snd_pcm,snd_hda_intel,snd_via82xx_modem,snd_atiixp_modem,snd_intel8x0m
snd 69322 21 snd_ac97_codec,snd_hwdep,snd_timer,snd_hda_codec_hdmi,snd_hda_codec_conexant,snd_pcm,snd_seq,snd_rawmidi,snd_hda_codec,snd_hda_intel,snd_via82xx_modem,snd_seq_device,snd_atiixp_modem,snd_intel8x0m,snd_seq_midi

I've found that killing "NetworkManager" (note the caps) resolves the issue and restarts the NetworkManager applet. I can then select a wifi network & continue.