Encoder false starts - never does any actual coding.

Lately, I have been getting a lot of false starts from Encoder.  I click on the start button, and the icons switch to running mode, but no export work starts.  My CPU is snoozing.  My GPU is asleep.  And Encoder shows nothing in the progress bar or monitor.  I have to manually close the process, reset the job, delete it, re-export it from PrP, and sometimes this works.  Often, I have to close out of everything, and restart, for Encoder to work.  Thoughts?