If you have Delphi Delphi 12 Athens, you can manually build the projects inside:

Source\MDShellExtensionsGroup.groupproj

Warning: To simplify build of the projects, some third parties libraries are located into Ext folder

Please take care that you have the same versions of those libraries installed in your IDE, or use the packages inside those projects to build and install components.

To manually install the SVGShellExtensions.dll follow these steps:

1. Close all the windows explorer instances which have the preview handler active or the preview handler was used (remember the dll remains in memory until the windows explorer was closed).

2. If you have already used the installer uninstall the components from system.

3. To install manually the dll run the Unregister_Register.cmd (run-as-administrator): notice that you must change the path into cmd file.