Hi there
Existing ArcGIS Desktop users—Help | ArcGIS Desktop
The ArcGIS Desktop 10.5 setup package is designed to detect and upgrade an existing installation of ArcGIS 10.1–10.4.1 for Desktop on the target system. The settings for the installation location, license manager (for concurrent use), or authorization information (for single use) are retained in the upgrade. After installation, any customizations, add-ons, or third-party applications previously installed might need to be reapplied. The installation folder cannot be changed for an upgrade.
If you wish to change the installation location, you will need to manually uninstall the previous installation through Add/Remove from the Windows Control Panel before installing ArcGIS Desktop 10.5 in the new location.
Your data that is on there should not be affected by this upgrade
