SymptomsUpgrade to Parallels Plesk Panel 10.2 freezes in the middle when you do it from Web Interface of Parallels Installer.
CauseDuring the upgrade, Parallels Plesk Panel installs the new version of Microsoft Visual C++ Redistributable Package. On completion of the package installation, Microsoft Windows opens a dialog to confirm the server restart. As you perform the upgrade through from your browser, you are unable to see this dialog and confirm the restart. Without the confirmation, the installation cannot go on, so it freezes.
Update Microsoft Visual C++ Redistributable Package to version 8.0.50727.4053 or higher before upgrading Parallels Plesk Panel.