I have Portable Apps in a folder on my C: drive, Windows 7. Foxit 9.3 is my default PDF reader. When I launched Foxit from PortableApps, it created a registry entry in HKEY-Current user-Software-Microsoft-Windows-CurrentVersion-Explorer-FileExts-PDF and created a string PDF portable or somesuch. As a result some of my PDF files would only open with the PortableAppp version, and some with the permanent installed version.If I closed PortableApps, the files requiring it would not open. I deleted the PDF portable string and now all is well again, but users should beware of the danger of using PortableApps Foxit.
The same thing happened with Sumatra. Not good.
Is this a problem with other apps? I am now afraid of using PortableApps for fear it might make nasty changes to host computers.