I had the same problem a couple of days ago, but it had nothing to do with the upgrade.
I got in touch with Apple Support, and they advised me to make sure my date and time were correctly set, that my firewall software was correctly set to allow iTunes, and to make sure that iTunes was a "trusted application" for my AV/Internet Security software.
I did all that, but nothing worked.
I then got back to them, and they advised me to completely uninstall iTunes and QuickTime, giving me extensive, detailed instructions on how to go about it.
I did that, rebooted, and re-installed the latest version of iTunes and QuickTime. (I had also disabled the AV - Kaspersky PURE, by the way). The installation seemed to go OK, and I duly rebooted as instructed. I also disabled Windows Firewall and kept Kaspersky disabled while I tried starting up iTunes. It started up, store login went OK, but the store was still blank. I couldn't even see my iTunes Store account.
I then completely uninstalled Kaspersky, left Windows Firewall disabled, rebooted and tried iTunes again. Still no good.
After much fiddling around, I found that I had another conflicting application on my machine: it was a video accelerator from a company called SpeedBit. Apparently it had been installed by RealPlayer, which I also use from time to time.
I uninstalled the SpeedBit Video Accelerator, and all other SpeedBit software, and, guess what?
iTunes suddenly started working!
I re-installed Kaspersky PURE, re-enabled Windows Firewall, etc., and iTunes still works OK.
My conclusion: iTunes is incompatible with any kind of video or download accelerators.
So, if you check the Support FAQ and follow all the instructions about Windows security settings, internet security and firewall settings, uninstalling and re-installing iTunes, etc., and it still doesn't work, also look on your machine for any other download accelerators, video accelerators, etc., get rid of them, and I think you might be OK.
Hope this helps.
Best regards to all
Message was edited by: Christopher Souter
You're right. Thanks.
"My conclusion: iTunes is incompatible with any kind of video or download accelerators.
So, if you check the Support FAQ and follow all the instructions about Windows security settings, internet security and firewall settings, uninstalling and re-installing iTunes, etc., and it still doesn't work, also look on your machine for any other download accelerators, video accelerators, etc., get rid of them, and I think you might be OK."
Close your iTunes,
Go to command Prompt -
(Win 7/Vista) - START/ALL PROGRAMS/ACCESSORIES, right mouse click "Command Prompt", choose "Run as Administrator".
(Win XP SP2 & above) - START/ALL PROGRAMS/ACCESSORIES/Command Prompt
In the "Command Prompt" screen, type in
netsh winsock reset
Hit "ENTER" key
Restart your computer.
If you do get a prompt after restart windows to remap LSP, just click NO.
Now launch your iTunes and see if it is working now.
If you are still having these type of problems after trying the winsock reset, refer to this article to identify which software in your system is inserting LSP:
Apple software on Windows: May see performance issues and blank iTunes Store
Got this from a guy called wiclee, credits of this post goes to him.
unfortunately I still get the message
"Unable to turn on Home sharing"
and I still can't access itunes store.
("Cannot connect to iTunes Store").....
tried eve LSP as recommended by apple, I got only Bonjour service running ...
Oh, yes, my ipad2 and wife's iphone4s as well as friends' iphone 4s can connect through my wifi to apple store...