The update of Parallels Panel has failed: “Syntax error in file panel.inf3: Error parsing Element”

Cause

The issue is temporary and caused by network connectivity issue to one of the autoinstaller mirrors.
Resolution

As a workaround use another autoinstaller mirror, add the following IP addresses for autoinstall-win.pp.parallels.com to the hosts file:

93.184.221.133 US, Kansas
68.232.34.73 US, California
72.21.81.253 US, California
46.22.75.111 EU, United Kingdom
72.21.89.132 EU, Germany

For example:

93.184.221.133 autoinstall-win.pp.parallels.com