diff --git a/src/main.rs b/src/main.rs
index 67e5638..f805302 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -19,20 +19,20 @@ fn main_inner() -> Result<(), Box<dyn std::error::Error>> {
     let (input_filename, is_zip) = reader::find_input_file()?;
     println!("Processing {}", input_filename);
     let lines = reader::read_data(&input_filename, is_zip)?;
-    let (header, body) = processor::split_into_header_and_body(&lines);
+    let (header, body) = processor::split_into_header_and_body(&lines)?;
 
-    let coalition_per_line = processor::divide_body_by_coalition(body);
+    let coalition_per_line = processor::divide_body_by_coalition(body)?;
 
-    let mut blue_writer = writer::create_writer(is_zip, &input_filename);
-    blue_writer.write_strings(header);
-    blue_writer.write_for_coalition(body, &coalition_per_line, Coalition::Blue);
+    let mut blue_writer = writer::create_writer(is_zip, &input_filename)?;
+    blue_writer.write_strings(header)?;
+    blue_writer.write_for_coalition(body, &coalition_per_line, Coalition::Blue)?;
 
-    let mut red_writer = writer::create_writer(is_zip, &input_filename);
-    red_writer.write_strings(header);
-    red_writer.write_for_coalition(body, &coalition_per_line, Coalition::Red);
+    let mut red_writer = writer::create_writer(is_zip, &input_filename)?;
+    red_writer.write_strings(header)?;
+    red_writer.write_for_coalition(body, &coalition_per_line, Coalition::Red)?;
 
-    let mut purple_writer = writer::create_writer(is_zip, &input_filename);
-    purple_writer.write_strings(header);
-    purple_writer.write_for_coalition(body, &coalition_per_line, Coalition::Purple);
+    let mut purple_writer = writer::create_writer(is_zip, &input_filename)?;
+    purple_writer.write_strings(header)?;
+    purple_writer.write_for_coalition(body, &coalition_per_line, Coalition::Purple)?;
     Ok(())
 }
diff --git a/src/processor.rs b/src/processor.rs
index d664822..b206d06 100644
--- a/src/processor.rs
+++ b/src/processor.rs
@@ -5,7 +5,7 @@ use std::hash::Hash;
 use crate::constants::{COMMENT, MINUS};
 use crate::tacview::{Coalition, CoalitionIDs};
 
-pub fn split_into_header_and_body<S, E>(lines: &[S]) -> Result<(&[S], &[S]), ProcessingError>
+pub fn split_into_header_and_body<S>(lines: &[S]) -> Result<(&[S], &[S]), ProcessingError>
 where
     S: AsRef<str>,
 {
@@ -15,7 +15,7 @@ where
             .as_ref()
             .chars()
             .next()
-            .ok_or(ProcessingError::LineIsEmptyError)?
+            .ok_or(ProcessingError::CannotSplitIntoHeaderAndBody)?
             == COMMENT
         {
             break;
@@ -147,7 +147,7 @@ impl LineType {
 }
 
 #[derive(Debug)]
-enum ProcessingError {
+pub enum ProcessingError {
     LineIsEmptyError,
     UnknownLineType,
     CannotSplitIntoHeaderAndBody,
diff --git a/src/reader.rs b/src/reader.rs
index 5f26aa0..f13a810 100644
--- a/src/reader.rs
+++ b/src/reader.rs
@@ -35,13 +35,13 @@ fn read_zip(buf: BufReader<File>) -> Result<Vec<String>, Error> {
     let mut archive = zip::ZipArchive::new(buf)?;
     let inner_file = archive.by_index(0)?;
     let inner_buf = BufReader::new(inner_file);
-    Ok(read_txt(inner_buf)?)
+    read_txt(inner_buf)
 }
 
 fn read_txt(buf: impl BufRead) -> Result<Vec<String>, Error> {
-    let lines: Vec<String> = buf
-        .lines()
-        .map(|l| l.expect("Could not read from the file"))
-        .collect();
+    let mut lines = vec![];
+    for line in buf.lines() {
+        lines.push(line?);
+    }
     Ok(lines)
 }
diff --git a/src/writer.rs b/src/writer.rs
index 70f1742..7fd8819 100644
--- a/src/writer.rs
+++ b/src/writer.rs
@@ -1,19 +1,20 @@
 use crate::constants::{EXTENSION_TXT, EXTENSION_ZIP};
 use crate::tacview::Coalition;
+use std::error::Error as ErrTrait;
 use std::fs::File;
-use std::io::Write;
+use std::io::{Error, Write};
 use zip::write::FileOptions;
 use zip::ZipWriter;
 
-pub fn create_writer(is_zip: bool, filename: &str) -> Box<dyn Write> {
+pub fn create_writer(is_zip: bool, filename: &str) -> Result<Box<dyn Write>, Box<dyn ErrTrait>> {
     let base_name = remove_extension(filename, is_zip);
     if is_zip {
-        Box::new(create_zipwriter(
+        Ok(Box::new(create_zipwriter(
             &format!("{base_name}{EXTENSION_ZIP}"),
             &format!("{base_name}{EXTENSION_TXT}"),
-        ))
+        )?))
     } else {
-        Box::new(create_textwriter(base_name))
+        Ok(Box::new(create_textwriter(base_name)?))
     }
 }
 
@@ -25,45 +26,45 @@ fn remove_extension(filename: &str, is_zip: bool) -> &str {
     }
 }
 
-fn create_textwriter(filename: &str) -> File {
-    File::create(filename).unwrap()
+fn create_textwriter(filename: &str) -> Result<File, Error> {
+    File::create(filename)
 }
 
-fn create_zipwriter(outer_name: &str, inner_name: &str) -> ZipWriter<File> {
-    let mut writer = ZipWriter::new(create_textwriter(outer_name));
-    writer
-        .start_file(
-            inner_name,
-            FileOptions::default().compression_method(zip::CompressionMethod::Deflated),
-        )
-        .unwrap();
-    writer
+fn create_zipwriter(outer_name: &str, inner_name: &str) -> Result<ZipWriter<File>, Error> {
+    let mut writer = ZipWriter::new(create_textwriter(outer_name)?);
+    writer.start_file(
+        inner_name,
+        FileOptions::default().compression_method(zip::CompressionMethod::Deflated),
+    )?;
+    Ok(writer)
 }
+
 pub trait StringWriter {
-    fn write_line<S: AsRef<str>>(&mut self, line: &S);
+    fn write_line<S: AsRef<str>>(&mut self, line: &S) -> Result<(), Error>;
 
-    fn write_strings<S: AsRef<str>>(&mut self, lines: &[S]);
+    fn write_strings<S: AsRef<str>>(&mut self, lines: &[S]) -> Result<(), Error>;
 
     fn write_for_coalition<S: AsRef<str>>(
         &mut self,
         lines: &[S],
         coalition_per_line: &[Coalition],
         coalition: Coalition,
-    );
+    ) -> Result<(), Box<dyn std::error::Error>>;
 }
 
 impl<T> StringWriter for T
 where
     T: Write,
 {
-    fn write_line<S: AsRef<str>>(&mut self, line: &S) {
-        writeln!(self, "{}", line.as_ref()).unwrap();
+    fn write_line<S: AsRef<str>>(&mut self, line: &S) -> Result<(), Error> {
+        writeln!(self, "{}", line.as_ref())
     }
 
-    fn write_strings<S: AsRef<str>>(&mut self, lines: &[S]) {
+    fn write_strings<S: AsRef<str>>(&mut self, lines: &[S]) -> Result<(), Error> {
         for line in lines {
-            self.write_line(line);
+            self.write_line(line)?;
         }
+        Ok(())
     }
 
     fn write_for_coalition<S: AsRef<str>>(
@@ -71,12 +72,19 @@ where
         lines: &[S],
         coalition_per_line: &[Coalition],
         coalition: Coalition,
-    ) {
+    ) -> Result<(), Box<dyn std::error::Error>> {
         assert_eq!(lines.len(), coalition_per_line.len());
-        lines
+
+        let iter = lines
             .iter()
             .zip(coalition_per_line)
             .filter(|(_, c)| **c == coalition || **c == Coalition::All)
-            .for_each(|(l, _)| self.write_line(l));
+            .map(|(l, _)| l);
+
+        for line in iter {
+            self.write_line(line)?;
+        }
+
+        Ok(())
     }
 }