Hi Rui. Thanks for the clarification.
Beside the PDFST other software (7-Zip, UnLocker i.e.) also was gone in my Windows 11 setup and had to be enabled by the ShellExView.
They now resides in the "reverse" key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Shell Extensions\Approved and is active.
Thanks again.
