If you accidentally update itunes 12.1, we first remove itunes 12.1 from our computer and try to resolve it in the following way.
1. Correctly uninstall itunes and its components in the order:
Because itunes involves multiple interdependent components, uninstall itunes and related components in the Control Panel-> Add or Remove Programs in the following order:
1) ittnes
2) Apple Software Update
3) Bonjour
4) Apple Mobile Device Support
5) Apple Application Support (32-bit)
6) Apple Application Support (64-bit)
(It is recommended that you restart your computer after uninstalling itunes and its components)
2. Install an older version of itunes
1 after the new version of itunes completely uninstall, open the Itools pc side, the device connected to the Itools PC side will be prompted to install the itunes component, click on " one-click Installation " will automatically download the installation. (If you uninstall the itunes component without prompting for the "Download itunes component" window, we recommend that you download the latest version of the installation again)
2 after the installation of the itunes component is complete, click Start itools to connect normally.
The solution is not the ultimate solution, this method is to remove the latest version of itunes to install the old version of itunes, this method is not expected to take me long.