diff --git a/file.lua b/file.lua
index 72c114a..2140bb1 100644
--- a/file.lua
+++ b/file.lua
@@ -187,6 +187,7 @@ function is_absolute_path(path)
     -- POSIX systems permit backslashes in filenames
     return path:sub(1,1) == '/'
   elseif os_path_separator == '\\' then
+    if path:sub(2,2) == ':' then return true end  -- DOS drive letter followed by volume separator
     local f = path:sub(1,1)
     return f == '/' or f == '\\'
   else
diff --git a/source_file.lua b/source_file.lua
index 54624b9..194ef9b 100644
--- a/source_file.lua
+++ b/source_file.lua
@@ -206,6 +206,7 @@ function is_absolute_path(path)
     -- POSIX systems permit backslashes in filenames
     return path:sub(1,1) == '/'
   elseif os_path_separator == '\\' then
+    if path:sub(2,2) == ':' then return true end  -- DOS drive letter followed by volume separator
     local f = path:sub(1,1)
     return f == '/' or f == '\\'
   else