De acordo com a resposta à pergunta Local de modelo personalizado no Office 2013 nos fóruns da Comunidade da Microsoft:
You can choose to override this setting by specifying a Personal Templates Folder. This can be done by going to File > Options > Save and manually entering a folder path. This needs to be done for each application, and for any application that does not have a Personal Templates path manually set, Office will create the Custom Office Templates folder the first time you save a template, and will set the Personal Templates path to this location.