Except for VST plugins on Windows the installation paths are fixed. If possible, HOFA plugins are installed in a subfolder. The following directories are used:

OS X:
„/Library/Audio/Plug-Ins/Component“ (Audio Unit)
„/Library/Audio/Plug-Ins/VST/HOFA “ (VST)
„/Library/Audio/Plug-Ins/VST3/HOFA“ (VST3)
„/Library/Application Support/Avid/Audio/Plug-Ins/HOFA“ (AAX)
„/Library/Application Support/Digidesign/DAE/Plug-Ins/HOFA“ (RTAS)

Windows:
„C:\Program Files (x86)\Common Files\VST3\HOFA“ (VST3 32-bit)
„C:\Program Files\Common Files\VST3\HOFA“ (VST3 64-bit)
„C:\Program Files (x86)\Common Files\Avid\Audio\Plug-Ins\HOFA“ (AAX 32-bit)
„C:\Program Files\Common Files\Avid\Audio\Plug-Ins\HOFA“ (AAX 64-bit)
„C:\Program Files (x86)\Common Files\Digidesign\DAE\Plug-Ins\HOFA“ (RTAS)

The installation directory for Windows/VST are shown in the overview window after clicking „INSTALL“/“UPDATE“/“REPAIR“/“UNINSTALL“/“APPLY CHANGES“ and can also be changed there.
The following paths are used:

„C:\Program Files (x86)\VstPlugins\HOFA“ (VST 32-bit)
„C:\Program Files\VstPlugins\HOFA“ (VST 64-bit)

Some DAWs (for example Cubase) set a default path for VST plugins in the Windows registry. If this path is set it will be used instead of the one above.