V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

PEBCAK
       Problem Exists Between Chair And Keyboard (slang)


The Free On-line Dictionary of Computing (30 December 2018):

PEBCAK
PBCAK
PBKAC
PEBKAC
PICNIC

    (Or "PEBKAC", "PBCAK", "PBKAC") Tech support
   shorthand for "Problem (Exists) between Chair and Keyboard".

   An alternative is "PICNIC" - "Problem In Chair, Not In
   Computer".

   An acronym commonly used by helpdesk technicians to indicate
   that a problem is due to the user rather than the system.

   See also UBD.

   (2012-08-26)