X7 vs X8 memory handling and release in Windows 10

X7 has been slow to start in Windows 10.  Later realized that every instance of X7, whether a document or simply a preview in File Explorer, creates a new instance in memory.  Which is fine, except upon closing X7 none of those instances release.  X8 creates an  instance in memory for documents and previews but it releases the preview memory when you quit the preview or move to another preview.  Whether that has to do with the WPIfilter, I don't know.

How can I get this memory releasing activity going in X7? And X6 for that matter?  Each of the residual memory instances uses only about 16K or RAM but they have individual entry points in RAM.  Also, when I "View Reliability History" in Windows 10 it shows a long list of X7 wpwin17.exe "Stopped Working" with exception codes and fault offsets.