Before installation/un-installation of LN it’s better to take back up in the other/external drive. Only copy the data folder from Lotus Notes folder and copy it to the other drive.
Bcoz there is only five files are important while upgrading your LN.
1. archive folder
5. .id file
All these are available in data folder. After copying the same uninstall the Old Version LN and install the same. After installation replace the above file with the newly installed LN. Best Regards “Mann”