Cheguei ao fim com a Ferramenta Analisador de configurações do Office , que apontou que eu tinha drivers de vídeo desatualizados que poderiam causar conflitos.
De acordo com o este artigo de suporte :
- You have at least two video cards installed in your computer and one of them is an NVidia card (different models) and the other is an Intel(R) HD Graphics 4000 card.
- The Disable hardware graphics acceleration option is not selected in the Outlook Options dialog.
There is a conflict between the hardware graphics acceleration feature and this combination of video hardware when the video drivers are not at the latest version.
Após atualizar os drivers Intel HD e NVidia, o Outlook foi aberto sem problemas.