Magento Warning: Header may not contain more than a single header, new line detected + Solution

If you are puzzled by the error message:

Warning: Header may not contain more than a single header, new line detected When dealing with a Magento migration, you might want to double check you have not accidentally added a new line character to the end of your base_url field when you were updating the core_config_data table.

I just did this using phpMyadmin’s nifty ajax editing feature however I must have hit return by accident. Simply editing them again and making sure there is absolutely no white space at the end of the URL and the problem is solved.