Connection Error in Zune with Windows 7 Phone.

There are two resolutions for this problem. You can create a new certificate, or reinstall Zune clean.

Create a new certificate and restore files
1. Create a new certificate

1. If your Zune software is open on your computer, close it, and then disconnect your phone from your computer.
2. Open Certificate Manager. To do this, click Start, type certmgr.msc in the Start search bar, and then press your Enter key.
3. In the pop-up window, click the Personal folder in the left column, and then the Certificates folder, in the right column.
4. Click the heading that says Issued By to sort the column, and then look for one or more certificates that read "zune-tuner://windowsphone/...".
5. Right-click each certificate file, click Delete, and then click Yes.
6. On the File menu, located in the menu bar of the window, click Exit.
7. Click Start and in the search box enter %userprofile%\Application Data\Microsoft\Crypto\RSA, and then press your Enter key.
8. Find the folder that begins in "S-1-5-21-".
9. Right-click the folder and then click Rename. Rename the folder so that it ends in .bak. This means, you will likely be adding ".bak" to the end of the number.
10. As soon as you're done, open your Zune software and connect your phone to your computer. This creates a new certificate and folder.

If you go back to your .bak certificate folder, and you may see some remaining files there. If this is the case, copy and paste these files in order to restore them to their previous state. To do this, see the following step.


2. Restore third-party files (if you have them)

To restore files, you have to copy files from the .bak folder and paste them into the original folder.

1. Click Start and in the search box enter %userprofile%\Application Data\Microsoft\Crypto\RSA, and then press your Enter key.
2. Click the RSA folder.
3. Find and open the folder that you renamed to end in .bak.
4. Press Ctrl+A on your keyboard to select all the files, and then press Ctrl+C to copy them.
5. Press the back button on your screen to return to the RSA folder.
6. Locate and open the new folder that begins in "S-1-5-21-" and does not end in .bak.
7. Press Ctrl+V to paste the files. When you see the warning "There is already a file with the same name in this location," click Don't Copy.
8. Close the folder.