Question:

How to set Adobe as Default PDF program instead of PowerPDF

Answer:

Change in PowerPDF

Open PowerPDF > File > Options > General > Startup > Default PDF Program > Return to Previous default application application

and

Open PowerPDF > File > Options > General > Integrations > select Disable - View PDF documents in Internet Explorer

Edit Registry

HKEY_CLASSES_ROOT\MIME\Database\Content Type\application/pdf

The CLSID listed to reference Adobe is HKEY_CLASSES_ROOT\MIME\Database\Content Type\vnd.adobe.acrobat-security-settings

You can copy the CLSID from this key and paste into the CLSID under HKEY_CLASSES_ROOT\MIME\Database\Content Type\application/pdf

CMD Prompt with Administrator

To enable PowerPDF as the default PDF Viewer:

"C:\Program Files (x86)\Nuance\Power PDF 20\bin\Defaultviewer.exe" /SetDefault

To Set the previous PDF program for Windows as the default PDF Viewer

"C:\Program Files (x86)\Nuance\Power PDF\bin\Defaultviewer.exe" /SetBack