The mail program you use does not open when you click on a mail address in your browser
Wrong configuration of the mailto parameter in the registry
To change the mailclient you prefer, you have to set a parameter in the registy. This parameter is of type REG_EXPAND_SZ which means that you cannot easily read it after an export.
You open the registry and navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Classes\mailto\shell\open\command and correct the setting to the one you want. e.g. "c:\programme\mutt\mutt.exe" %1
When you export this it looks like:
Windows Registry Editor Version 5.00
About the Author
Wim Peeters is electronics engineer with an additional master in IT and over 30 years of experience including time spent in support, development, consulting, training and database administration. Wim has worked with SQL Server since version 6.5. He has developed in C/C++, Java and C# on Windows and Linux in different European countries and different European languages. He writes knowledge base articles to solve IT problems and publishes them on the Lubby Knowledge Platform where he is one of the most important contributors and the main developer.