Q: Recently updated to itunes 10.6.1, but during update it says itunes does not have a valid signature and update fails ,now older version is not able to connect to itunes store

Try to download iTunes again from here, choose the option to save before running the iTunesSetup file.

If the signature error pops up again, take a look at this -> iTunes: Windows reports that "iTunesSetup.exe is not a valid Win32 application"

Do you still see the iTunes Store connection issue after updating?

(Apologies for butting in, wha.)

now older version is not able to connect to itunes store error 306. I am using windows 7.

If you still get the 306 after updating to 10.6.1.7, perhaps try the following user tip:

iTunes for Windows 9.0.x: Error 306