diff --git a/src/files.jl b/src/files.jl
index e0421d95..f6bc8baf 100644
--- a/src/files.jl
+++ b/src/files.jl
@@ -51,7 +51,9 @@ function include_pt_in_file(filename::AbstractString, mark::AbstractString,
     # tries to avoid a problem in Windows as shown here:
     #
     #   https://discourse.julialang.org/t/find-what-has-locked-held-a-file/23278
-    orig = ""
+    orig = nothing
+    io   = nothing
+    r    = nothing
     GC.gc()
 
     # Backup the original file if required.