Encountering error "The upgrade patch cannot be installed by the Windows Installer service because the program to be upgraded may be missing or the upgrade patch may update a different version of the program. Verify that the program to be upgraded exists on your computer and that you have the correct upgrade patch." when trying to install ArcGIS-1061-BGDT-GS-Patch for ArcGIS Desktop 10.6.1.
ArcGIS Desktop version 10.6.1 (9270) + windows server 2012 R2 (64 bit)
Used both the method by directly executing the ArcGIS-1061-BGDT-GS-Patch.msp and by executing it from command prompt as an administrator using the following command:
msiexec.exe /p [location of Patch]\ArcGIS-1061-<Product>-GS-Patch.msp
"ArcGIS-1061-DT-GU-Patch" was successfully installed on this machine but ArcGIS-1061-BGDT-GS-Patch couldn't.