Messages quit working following 10.9.4 update

Question

Following the update to 10.9.4, I am unable to log into messages on my MacbookPro.  When I go to messages I am shown as Offline and when attempting to login with Apple ID, I always get the note "An error occurred on activation, try again."   I am able to use it on my iPad.  Having searched the Support pages, nothing has worked.  Here is information on my machine from EtreCheck.  Any assistance getting messages up on my Macbook would be appreciated.
EtreCheck version: 1.9.12 (48)
Report generated July 25, 2014 at 8:48:49 AM PDT
Hardware Information:
  MacBook Pro (15-inch, Early 2011) (Verified)
  MacBook Pro - model: MacBookPro8,2
  1 2.2 GHz Intel Core i7 CPU: 4 cores
  8 GB RAM
Video Information:
  Intel HD Graphics 3000 - VRAM: 512 MB
  Color LCD 1440 x 900
  AMD Radeon HD 6750M - VRAM: 1024 MB
System Software:
  OS X 10.9.4 (13E28) - Uptime: 1 day 23:15:31
Disk Information:
  Hitachi HTS725050A9A362 disk0 : (500.11 GB)
  EFI (disk0s1) <not mounted>: 209.7 MB
  Macintosh HD (disk0s2) / [Startup]: 459.25 GB (250.32 GB free)
  Recovery HD (disk0s3) <not mounted>: 650 MB
  BOOTCAMP (disk0s4) /Volumes/BOOTCAMP: 40 GB (6.76 GB free)
  MATSHITADVD-R   UJ-8A8 
USB Information:
  Apple Inc. FaceTime HD Camera (Built-in)
  Apple Inc. Apple Internal Keyboard / Trackpad
  Apple Inc. BRCM2070 Hub
  Apple Inc. Bluetooth USB Host Controller
  Apple Computer, Inc. IR Receiver
FireWire Information:
  Seagate GoFlex Desk Mac 800mbit - 800mbit max
  EFI (disk1s1) <not mounted>: 209.7 MB
  FreeAgent GoFlex Drive (disk1s2) /Volumes/FreeAgent GoFlex Drive: 2 TB (691.06 GB free)
Thunderbolt Information:
  Apple Inc. thunderbolt_bus
Gatekeeper:
  Mac App Store and identified developers
Kernel Extensions:
  [loaded] com.seagate.driver.PowSecDriverCore (5.1.1) Support
  [not loaded] com.seagate.driver.PowSecLeafDriver_10_4 (5.1.1) Support
  [loaded] com.seagate.driver.PowSecLeafDriver_10_5 (5.1.1) Support
  [not loaded] com.seagate.driver.SeagateDriveIcons (5.1.1) Support
Launch Daemons:
  [loaded] com.adobe.fpsaud.plist Support
  [loaded] com.google.keystone.daemon.plist Support
  [loaded] com.oracle.java.Helper-Tool.plist Support
  [loaded] com.oracle.java.JavaUpdateHelper.plist Support
Launch Agents:
  [running] com.Affinegy.InstaLANa.plist Support
  [loaded] com.google.keystone.agent.plist Support
  [loaded] com.lexmark.bmspecificlaunchd.plist Support
  [loaded] com.lexmark.lxknetlaunchd.plist Support
  [loaded] com.oracle.java.Java-Updater.plist Support
  [running] com.seagate.SeagateStorageGauge.plist Support
User Launch Agents:
  [loaded] .dat00fc.000 (hidden)
  osascript -e tell application "Folder Actions Dispatcher" to tick
  [loaded] com.divx.agent.postinstall.plist Support
User Login Items:
  Garmin Lifetime Map Updater
  iTunesHelper
  Dropbox
Internet Plug-ins:
  FlashPlayer-10.6: Version: 14.0.0.145 - SDK 10.6 Support
  Default Browser: Version: 537 - SDK 10.9
  Flash Player: Version: 14.0.0.145 - SDK 10.6 Support
  QuickTime Plugin: Version: 7.7.3
  o1dbrowserplugin: Version: 5.4.2.18903 Support
  GarminGpsControl: Version: 4.1.0.0 Release - SDK 10.7 Support
  googletalkbrowserplugin: Version: 5.4.2.18903 Support
  Silverlight: Version: 5.1.20913.0 - SDK 10.6 Support
  JavaAppletPlugin: Version: Java 7 Update 60 Check version
Audio Plug-ins:
  BluetoothAudioPlugIn: Version: 1.0 - SDK 10.9
  AirPlay: Version: 2.0 - SDK 10.9
  AppleAVBAudio: Version: 203.2 - SDK 10.9
  iSightAudio: Version: 7.7.3 - SDK 10.9
iTunes Plug-ins:
  Quartz Composer Visualizer: Version: 1.4 - SDK 10.9
User Internet Plug-ins:
  Google Earth Web Plug-in: Version: 7.1 Support
3rd Party Preference Panes:
  Flash Player  Support
  Java  Support
Time Machine:
  Skip System Files: NO
  Mobile backups: ON
  Auto backup: YES
  Volumes being backed up:
  Macintosh HD: Disk size: 427.71 GB Disk used: 194.58 GB
  Destinations:
  FreeAgent GoFlex Drive [Local] (Last used)
  Total size: 2 
  Total number of backups: 68
  Oldest backup: 2011-08-16 03:50:19 +0000
  Last backup: 2014-07-19 15:46:30 +0000
  Size of backup disk: Excellent
  Backup size 2  > (Disk size 427.71 GB X 3)
  Time Machine details may not be accurate.
  All volumes being backed up may not be listed.
Top Processes by CPU:
      9% backupd
      2% WindowServer
      1% mds
      1% opendirectoryd
      1% fontd
Top Processes by Memory:
  254 MB mds_stores
  172 MB softwareupdated
  156 MB Safari
  139 MB com.apple.IconServicesAgent
  115 MB Mail
Virtual Memory Information:
  3.37 GB Free RAM
  2.72 GB Active RAM
  592 MB Inactive RAM
  1.33 GB Wired RAM
  12.18 GB Page-ins
  0 B Page-outs

Answer 1

This could be a complicated problem to solve, as there are many possible causes for it. Test after taking each of the following steps that you haven't already tried. Back up all data before making any changes.
Before proceeding, test on another network, if possible. That could be a public Wi-Fi hotspot, if your computer is portable, or a cellular network if you have a mobile device that can share its Internet connection. If you find that iMessage works on the other network, the problem is in your network or at your ISP, not in your computer.
Step 1
Check the status of the service. If the service is down, wait tor it to come back up. There may be a localized outage, even if the status indicator is green.
Step 2
Sign out of iMessage on all your Apple devices. Log out and log back in. Try again to sign in.
Step 3
Restart your router and your broadband device, if they're separate. You may have to skip this step if you don't control those devices.
Step 4
From the menu bar, select
           ▹ About This Mac
Below the "OS X" legend in the window that opens, the OS version appears. Click the version line twice to display the serial number. If the number is missing or invalid according to this web form, take the machine to an Apple Store or other authorized service center to have the problem corrected.
Step 5
Take the steps suggested in this support article. If you don't understand some of the steps or can't carry them out, ask for guidance.
Step 6
From the menu bar, select
           ▹ System Preferences... ▹ Network
If the preference pane is locked, click the lock icon in the lower left corner and enter your password to unlock it. Then click the Advanced button and select the Proxies tab. If the box marked SOCKS Proxy is checked, uncheck it. You don’t need to change any other settings in the window. Click OK and then Apply. Test.
The result may be that you can't connect to the Internet at all. Revert the change if that happens, or if iMessage still doesn't work. Remember that you must Apply any changes you make in the preference pane before they take effect.
Step 7
Select from the menu bar
           ▹ System Preferences… ▹ Flash Player ▹ Storage
and click
          Block all sites from storing information on this computer
Close the preference pane.
Step 8
Make sure you know the ID and password you use with iMessage. Launch the Keychain Access application in any of the following ways:
☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
☞ Open LaunchPad. Click Utilities, then Keychain Access in the icon grid.
Use the search box in the toolbar of the Keychain Access window to find and delete all items with "iMessage" or "com.apple.idms" in the name. Log out and log back in.
Step 9
Enable guest logins* and log in as Guest. Don't use the Safari-only “Guest User” login created by “Find My Mac.”
While logged in as Guest, you won’t have access to any of your personal files or settings. Applications will behave as if you were running them for the first time. Don’t be alarmed by this; it’s normal. If you need any passwords or other personal data in order to complete the test, memorize, print, or write them down before you begin.
Test while logged in as Guest. After testing, log out of the guest account and, in your own account, disable it if you wish. Any files you created in the guest account will be deleted automatically when you log out of it.
*Note: If you’ve activated “Find My Mac” or FileVault, then you can’t enable the Guest account. The “Guest User” login created by “Find My Mac” is not the same. Create a new account in which to test, and delete it, including its home folder, after testing.
If iMessage worked in the guest account, stop here and post your results.
Step 10
Start up in safe mode and log in to the account with the problem. You must hold down the shift key twice: once when you start up, and again when you log in.
Note: If FileVault is enabled, or if a firmware password is set, or if the startup volume is a Fusion Drive or a software RAID, you can’t do this. Ask for further instructions.
Safe mode is much slower to start and run than normal, with limited graphics performance, and some things won’t work at all, including sound output and Wi-Fi on certain models. The next normal startup may also be somewhat slow.
The login screen appears even if you usually log in automatically. You must know your login password in order to log in. If you’ve forgotten the password, you will need to reset it before you begin.
Test while in safe mode. After testing, restart as usual (i.e., not in safe mode) and test again.
If iMessage worked in safe mode, but still doesn't work when you restart in "normal" mode, stop here and post your results.
Step 11
Triple-click anywhere in the line below on this page to select it:
/Library/Preferences/com.apple.apsd.plist
Right-click or control-click the highlighted line and select
          Services ▹ Reveal in Finder (or just Reveal)
from the contextual menu.* A folder should open with an item selected. Move the selected item to the Trash. You may be prompted for your administrator login password. Restart the computer and empty the Trash.
*If you don't see the contextual menu item, copy the selected text to the Clipboard by pressing the key combination  command-C. In the Finder, select
          Go ▹ Go to Folder...
from the menu bar and paste into the box that opens by pressing command-V. You won't see what you pasted because a line break is included. Press return.
Step 12
Reset the NVRAM.
Step 13
Reinstall OS X.
Step 14
If none of the above steps resolves the issue, make a "Genius" appointment at an Apple Store, or contact Apple Support.