diff --git a/src/Jupyter2Pluto.jl b/src/Jupyter2Pluto.jl
index b2e0d3b..a65f2c2 100644
--- a/src/Jupyter2Pluto.jl
+++ b/src/Jupyter2Pluto.jl
@@ -153,9 +153,12 @@ end
 function jupyter2pluto(jupyter_file)
     jupyter_cells = try
         content = JSON.parsefile(jupyter_file)
+        if !isJupyterNotebook(content)
+          error("File is not Jupyter Notebook")
+        end
         content["cells"]
     catch ex
-        error("Jupyter notebook parse error")
+        error("Jupyter notebook parse error: ", ex)
     end
     pluto_cells = PlutoCell[]
     for cell in jupyter_cells
@@ -295,4 +298,12 @@ function getFileName(str::AbstractString)
     end
 end
 
+function isJupyterNotebook(content)
+  try
+    return haskey(content, "cells") && haskey(content, "metadata")
+  catch e
+    return false
+  end
+end
+
 end # module