diff --git a/PyTeX/build/build/builder.py b/PyTeX/build/build/builder.py
index 04b7689..ee4da2a 100644
--- a/PyTeX/build/build/builder.py
+++ b/PyTeX/build/build/builder.py
@@ -6,6 +6,8 @@ import shutil
 
 from .enums import PyTeXRootDirType
 from .pytex_config import PyTeXConfig
+from ...exceptions import PyTeXException
+from ...format.errors import PyTeXError
 from ...format.formatting_config import FormattingConfig
 from ...logger import logger
 from .constants import *
@@ -304,7 +306,11 @@ class PyTeXBuilder:
         logger.info(f"Needing to build {len(self._files_to_build)} many files.")
         self._check_output_directory_integrity()  # 1ms
         logger.info(f"Starting build")
-        self._build_files()  # 53 ms
+        try:
+            self._build_files()  # 53 ms
+        except PyTeXError as e:
+            e.add_explanation('while building output files')
+            raise e
         logger.info(f"Built files")
         self._move_files()
         self._write_version_info()
diff --git a/PyTeX/format/dtx_formatter.py b/PyTeX/format/dtx_formatter.py
index 1391c60..0c0adda 100644
--- a/PyTeX/format/dtx_formatter.py
+++ b/PyTeX/format/dtx_formatter.py
@@ -25,7 +25,7 @@ class DTXFormatter(TexFormatter):
             files.append(self.name + '.ins')
         return files
 
-    def _get_internal_file(self) -> str:
+    def _get_internal_file(self, comment: bool) -> str:
         g = GenericText(INS_FILE)
         switcher = {
             TeXType.TeXPackage: '.sty',
@@ -37,46 +37,58 @@ class DTXFormatter(TexFormatter):
             preamble='',  # TODO
             postamble='',  # TODO
             guards=', '.join(self.config.docstrip_guards),
-            padding=False
+            padding=False,
+            comment=comment
         )
 
-    def _get_drv_file(self) -> str:
+    def _get_drv_file(self, comment: bool) -> str:
         g = GenericText(DRV_FILE)
         return g.format(
             documentclass='l3doc',  # TODO
             preamble='',  # TODO
             infile=self.name + '.dtx',
-            padding=False
+            padding=False,
+            comment=comment
         )
 
     def format_pre_header(self) -> None:
-        self._shipout_line(r'% \iffalse meta-comment')
+        if self.current_file_name().endswith('.dtx'):
+            self._shipout_line(r'% \iffalse meta-comment')
 
     def format_post_header(self) -> None:
-        self._shipout_line('%</internal>')
-        self._shipout_line(
-            self._get_internal_file()
-        )
-        self._shipout_line('%<*internal>')
-        self._shipout_line('%')
-        self._shipout_line(
-            '%<{outtype}>{provides}'.format(
-                outtype=self.config.tex_out_type.value,
-                provides=self._get_provides_text(
-                    self.config.tex_out_type.value.capitalize()
+        if self.current_file_name().endswith('.dtx'):
+            self._shipout_line('%</internal>')
+            self._shipout_line(
+                self._get_internal_file(comment=True)
+            )
+            self._shipout_line('%<*internal>')
+            self._shipout_line('%')
+            self._shipout_line(
+                '%<{outtype}>{provides}'.format(
+                    outtype=self.config.tex_out_type.value,
+                    provides=self._get_provides_text(
+                        self.config.tex_out_type.value.capitalize()
+                    )
                 )
             )
-        )
-        self._shipout_line('%')
-        self._shipout_line('%<*driver>')
-        self._shipout_line(
-            self._get_drv_file()
-        )
-        self._shipout_line('%</driver>')
-        self._shipout_line(r'% \fi')
-        self._shipout_line('%')
-        self.mode = FormatterMode.meta
-        pass
+            self._shipout_line('%')
+            self._shipout_line('%<*driver>')
+            self._shipout_line(
+                self._get_drv_file(comment=True)
+            )
+            self._shipout_line('%</driver>')
+            self._shipout_line(r'% \fi')
+            self._shipout_line('%')
+            self.mode = FormatterMode.meta
+            pass
+        elif self.current_file_name().endswith('.ins'):
+            self._shipout_line(
+                self._get_internal_file(comment=False)
+            )
+        elif self.current_file_name().endswith('.drv'):
+            self._shipout_line(
+                self._get_drv_file(comment=False)
+            )
 
     def _post_process_line(self, line: str) -> str:
         line = line.rstrip(' %\n')
diff --git a/PyTeX/format/generic_text.py b/PyTeX/format/generic_text.py
index 9e09c01..32bfc86 100644
--- a/PyTeX/format/generic_text.py
+++ b/PyTeX/format/generic_text.py
@@ -63,13 +63,19 @@ class GenericText:
 
     def format(self, **kwargs) -> str:
         padding = True
+        comment = True
         if 'padding' in kwargs.keys():
             padding = kwargs['padding']
             kwargs.pop('padding', None)
+        if 'comment' in kwargs.keys():
+            comment = kwargs['comment']
+            kwargs.pop('comment', None)
         lines = []
         for line in self.text:
             try:
-                line = '% ' + line.rstrip().format(**kwargs)
+                line = line.rstrip().format(**kwargs)
+                if comment:
+                    line = '% ' + line
                 if padding:
                     line = line.ljust(79) + '%'
                 if len(line) > 80:
diff --git a/PyTeX/format/tex_formatter.py b/PyTeX/format/tex_formatter.py
index 88373ad..e1694a0 100644
--- a/PyTeX/format/tex_formatter.py
+++ b/PyTeX/format/tex_formatter.py
@@ -82,6 +82,7 @@ class TexFormatter(PyTeXFormatter, ABC):
             raise NotImplementedError
         else:
             self._output_file = out_file.open('w')
+        self.mode = FormatterMode.normal
 
     def close_output_stream(self) -> None:
         self._output_file.close()