Emacs 24.5.1 in cygwin x64, Windows 7, gpg (GnuPG) 2.0.21 (Gpg4win 2.2.0)
Visited file ~/somefile.gpg
Got error "Opening input file" "Can't decrypt" "Exit".
Debugger entered--Lisp error: (file-error "Opening input file" "Can't decrypt" "Exit")
signal(file-error ("Opening input file" "Can't decrypt" "Exit"))
epa-file--find-file-not-found-function()
run-hook-with-args-until-success(epa-file--find-file-not-found-function)
#[257 "..." [#<killed buffer> "~/somefile.gpg" (nil) file-exists-p file-readable-p kill-buffer signal file-error "File is not readable" run-hook-with-args-until-success find-file-not-found-functions t] 5 "\n\n(fn IGNORED)"]((file-error "Opening input file" "Can't decrypt" "Exit"))
funcall(#[257 "..." [#<killed buffer> "~/somefile.gpg" (nil) file-exists-p file-readable-p kill-buffer signal file-error "File is not readable" run-hook-with-args-until-success find-file-not-found-functions t] 5 "\n\n(fn IGNORED)"] (file-error "Opening input file" "Can't decrypt" "Exit"))
find-file-noselect-1(#<killed buffer> "~/somefile.gpg" nil nil "~/somefile.gpg" (10696049115278578 2661856658))
find-file-noselect("~/somefile.gpg" nil nil t)
eval((find-file-noselect "~/somefile.gpg" nil nil t) nil)
eval-last-sexp-1(nil)
eval-last-sexp(nil)
call-interactively(eval-last-sexp nil nil)
command-execute(eval-last-sexp)
.emacs, emacs.bat to launch just in case.