Today I took a look into the system.log from one of our Magento shops and I saw that there is an error:

2019-01-20T09:05:52+00:00 CRIT (2): Not valid template file:frontend/base/default/template/checkout/cart/mini.phtml

Does anyone know where I have to look to change the path where it's looking for? The file doesn't exists on the server so the file that is asking for mini.phtml needs te be located, but how can I know which file is asking for mini.phtml?

Thanks!