I am moving this information over from the old forums, as it appears that quite a few people are having this error.
The solution I have seen so far that appears to work for most people is to simply exit the launcher and open it again (and again if necessary). It may take a number of tries, but it appears to work eventually.
I do not currently have access to a system experiencing this to dink around and find another solution, but I am on the lookout for any other potential fixes.
Some other solutions I have seen that work in certain cases, but not all:
Applying the patch in Safemode with Networking: http://us.blizzard.com/support/article.xml?articleId=21148
Configuring Internet Options
Go to the Control Panel and open up Internet Options.
Click on the Connections tab.
Click the button called "LAN Settings"
Uncheck all of the options on that screen.
Then try again.
If that does not work, go back in and check the box to "Automatically Detect Settings" and test once more.
NOTE: Please make sure that you have the most current version of Internet Explorer, even if you do not normally use it to browse the web. Also, double-check that it is not set to run in offline mode.
Make sure that you are on the administrative account for the computer, and if you are on Windows Vista or Windows 7 try right-clicking on the shortcut and running as administrator instead of double-clicking.
If that does not work, you can also try to take ownership of the entire World of Warcraft folder, which can sometimes fix this.
How to take ownership in Vista/7: http://www.howtogeek.com/howto/windows-vista/add-take-ownership-to-explorer-right-click-menu-in-vista/
How to take ownership in XP: http://support.microsoft.com/kb/308421
If you are still having issues, check to make sure that your antivirus is not detecting a false-positive in the program and blocking the patch. If it is, you will need to flag the file as safe.
I have also seen people have success by disabling their antivirus temporarily.
University Network/Public connection
Many public connections will block the patch from downloading. You can contact the network administrator to configure the network to allow the patches, or you can download the necessary files from an external site.
file on sendspace to anyone who cant use hotfileposted by Bolur further down this thread
Other solutions players have reported:
My Realmlist was set for Europe and therefore couldnt download the patch until the europe servers would normally get it. Check your realmlists to see if my problem was also yours.reported by Renay
World of warcraft > Data > EnGB or EnUS > Realmlist.wtf
it should be
set realmlist us.logon.worldofwarcraft.com
set patchlist enUS.patch.battle.net:1119/patch
set realmlistbn ""
set portal us
Finally it started to download and install the updates what I did was delete the Updates, Temp, and Chache folders something inside of those 3 folders is what was stopping me from updating.reported by Lorken
Try closing the updater and re-opening it from the updater file in your World of Warcraft folder (wow-126.96.36.1997-to-188.8.131.522-enUS-tools-downloader). I was having the same problem, and this immediately fixed it for me.reported by Engineer
Go into your World of Warcraft folder and double-click "Repair"reported by Jameson
I was having the problem and the multiple clicking was not working, but I ran the repair tool and it righted itself.
On Vista:Reported by Taylynn
1.) open your browser and go to tools. ( Internet Exp. over to the right by the blue ? )
2.) go to internet options
3.) go to advanced
4.) you will see different sections (such as Accessibility, Browsing, etc) find Security
5.) under Security, next to the first few check boxes you should see
"Allow active content to run in files on my Computer*"
6.) If that box is not checked off select it to check mark it.
If you're like me and have McAfee and got this error that the launcher cannot receive the patch information then try this:Reported by Yehvon
-Open up McAfee and go to the firewall settings
-Open up the tab that shows a big list of of Program Permissions
-Everywhere you see a "WoW.exe" WoW launcher" "blizzard downloader/uploader" change from outgoing to full (i had this set before but this patch made McAfee ask for permission so I went to checked it again)
-Exit and restart your computer
-Open wow launcher and it should work
OK. so i figured it out i think for all you MAC users! All you have to do is refresh and get a new DHCP. Im not really sure what that means but it worked. this is how you do it!reported by Egyedues
Click the apple (top left)
Click System Preference
Then click on either airport of ethernet. (ethernet if your hard wired on a desktop and Airport if your using wifi)
The click the advanced button at the bottom right.
Click the TCP/IP tab.
Then click renew DHCP lease
Any further threads on this topic will be locked to avoid spamming out other issues on this forum.