If you need to uninstall and reinstall your authorized copy of ArcGIS (for example, if you are reformatting your hard drive or switching to a new computer or you have entered your eva code in once and it did not authorize) please follow these instructions before uninstalling the software.

1. Open up ArcGIS Administrator (located in the ArcGIS program group in your Start Menu).
2. In the left-hand pane, click the Support Operations folder, and the Deauthorize button.
3. Follow the instructions to remove the core product and any selected extensions from your machine. https://desktop.arcgis.com/en/desktop/latest/get-started/administering-desktop/authorizing-arcgis-single-use-products-and-features.htm\
4. Uninstall ArcGIS for Desktop (Control Panel > Programs and Features).
5. Reinstall ArcGIS for Desktop.
6. Authorize software.