MySQL Notifier Error
The error appears due to a corrupted configuration file or some dummy MySQL services (Leftovers from server installations not completely removed, this is due to the auto-detect mysql services functionality). Please make sure you're running the latest Notifier version available (that can be downloaded at mysql downloads page).

How to solve the corrupted file configuration:


See the answer from Colin Pickard.


How to solve the dummy MySQL services leftovers:


If the problem persists, open a Run command window and type the following: 


  services.msc

Take note of any MySQL service that shouldn't be listed (attempted uninstall before). 
Open an Admin rights command window and type the command: 


  sc delete "&lt; Dummy_service_name_here >".



Restart Notifier and see if that corrected the problem.

If a similar error still appears afterwards, check if the stack trace shows the word CreateScheduledTask somewhere, that would mean something is wrong when Notifier tries to add a schedule task at startup to check for updates of any installed MySQL product. 

A workaround is to open in notepad the settings.config file that was re-generated. Inside the file, look for a property called "AutoCheckForUpdates" and change the default value of "True" for "False" and run Notifier again, as noted in this post.