If you would like to install a newer version of JChem for Excel or JChem for Office on your computer, first you have to uninstall the previously installed version manually.
To uninstall the program, navigate to Control Panel > Programs > Programs and Features.
During the uninstallation process, the User Account Control (UAC) settings are turned off to avoid constant notifications about the registry changes. This is normal and after the software is uninstalled, the settings are changed back to the original state.
It is possible to install JChem for Office beside JChem for Excel already available on your computer, but only if they have the same version number, in this case, it is listed as a separate entity, see the figure below.
If you would like to upgrade to a newer version of JChem for Office, please uninstall both ChemAxon JChem for Excel and JChem for Office applications. If you install JChem for Excel and Office separately, please make sure, that they have the same released version number.
If you have different ChemAxon products installed on your computer, please, make sure that they have the same released version.
You can see the process of uninstalling and upgrading in this video: