How to solve Invalid Xml syntax error after updated an older Visual Studio project

Error message:
This application has failed to start because the application configuration is incorrect. Review the manifest file for possible errors.
Reinstalling the application may fix this problem. For more details, please see the application event log.

In EventView, the error message is:
Activation context generation failed for XXXXX
XXXX on line 1. Invalid Xml syntax.

The first line in config file is
<?xml version="1.0" encoding="Windows-1252"?>

Solution:
Change to
<?xml version="1.0" encoding="utf-8"?>