Got feedback from the support desk:
Please uninstall any existing Nik version on your computer (Google and/or DxO versions if relevant).
If relevant, please manually check there’s no Nik sub-repositories (“Analog Efex Pro 2”, “Color Efex Pro 4”, “Dfine 2”, “HDR Efex Pro 2”, “Selective Tool”, “Sharpener Pro 3”, “Silver Efex Pro 2”, “Viveza 2”) in:
*C:\Program Files\Adobe\Adobe Photoshop Elements \Plug-ins\Google (for Photoshop Elements versions)
*C:\Program Files\Adobe\Adobe Photoshop Elements \Plug-ins\DxO (for Photoshop Elements versions)
*C:\Program Files\Adobe\Adobe Photoshop CS \Plug-ins\Google (for Photoshop CS versions)
*C:\Program Files\Adobe\Adobe Photoshop CS \Plug-ins\DxO (for Photoshop CS versions)
*C:\Program Files\Adobe\Adobe Photoshop CC \Plug-ins\Google (for Photoshop CC versions before 2015.5)
*C:\Program Files\Adobe\Adobe Photoshop CC \Plug-ins\DxO (for Photoshop CC versions before 2015.5)
C:\Program Files\Common Files\Adobe\Plug-Ins\CC\Google (for Photoshop CC versions above 2015.5)
C:\Program Files\Common Files\Adobe\Plug-Ins\CC\DxO (for Photoshop CC versions above 2015.5)
Then, please delete all Nik related repositories from C:\ProgramData\Google and C:\ProgramData\DxO
Finally, please re-install latest Nik Collection by DxO version.
I tried. Still the same: Silver Efex disk is full… Have to go back to Nik 3