| Autres tabs | Several factors can contribute to this issue. One common cause is that the Office 2019 C2R retail installation is not properly configured or activated. If the installation is not activated, it cannot be converted to a volume-licensed installation. Another cause is that the user's Office 2019 C2R retail installation is not compatible with the organization's volume licensing agreement. Additionally, if the organization's volume licensing agreement is not properly configured or if the necessary registry entries are not present, the conversion may not be possible.