If you are having issues with opening your flash tool. Make sure to download the latest version supported by your computers operating system.
Here you can learn more about the flash tool for Xperia™ devices, which is a desktop application that you can use to flash Sony software on your unlocked Xperia™ device. This is useful if you’ve for example flashed a custom ROM on your device, and want to go change to a standard Sony software. This flash tool can only be used by Xperia™ devices having an unlocked bootloader. Please note that your phone still stays unlocked, and that the warranty may still be voided.
Also note that only a limited number of phone models and software versions are supported by this tool, as we are currently running it as a beta version.