diff --git a/cli/options.go b/cli/options.go
index 304993ba..567ac5ac 100644
--- a/cli/options.go
+++ b/cli/options.go
@@ -238,7 +238,7 @@ func GetEnvFromFile(currentEnv map[string]string, workingDir string, filename st
 
 	file, err := os.Open(dotEnvFile)
 	if err != nil {
-		return envMap, err
+		return envMap, errors.Wrapf(err, "failed to read %s", dotEnvFile)
 	}
 	defer file.Close()
 
@@ -250,7 +250,7 @@ func GetEnvFromFile(currentEnv map[string]string, workingDir string, filename st
 		return v, true
 	})
 	if err != nil {
-		return envMap, err
+		return envMap, errors.Wrapf(err, "failed to read %s", dotEnvFile)
 	}
 	for k, v := range env {
 		envMap[k] = v
diff --git a/dotenv/fixtures/invalid1.env b/dotenv/fixtures/invalid1.env
index 38f7e0e8..18ed705c 100644
--- a/dotenv/fixtures/invalid1.env
+++ b/dotenv/fixtures/invalid1.env
@@ -1,2 +1,8 @@
+# some comments
+foo="
+  a
+  multine
+  value
+"
 INVALID LINE
-foo=bar
+zot=qix
\ No newline at end of file
diff --git a/dotenv/godotenv.go b/dotenv/godotenv.go
index c1c12eaf..ae34ffa9 100644
--- a/dotenv/godotenv.go
+++ b/dotenv/godotenv.go
@@ -15,13 +15,9 @@ package dotenv
 
 import (
 	"bytes"
-	"fmt"
 	"io"
 	"os"
-	"os/exec"
 	"regexp"
-	"sort"
-	"strconv"
 	"strings"
 
 	"github.com/compose-spec/compose-go/template"
@@ -72,21 +68,6 @@ func Load(filenames ...string) error {
 	return load(false, filenames...)
 }
 
-// Overload will read your env file(s) and load them into ENV for this process.
-//
-// Call this function as close as possible to the start of your program (ideally in main).
-//
-// If you call Overload without any args it will default to loading .env in the current path.
-//
-// You can otherwise tell it which files to load (there can be more than one) like:
-//
-//	godotenv.Overload("fileone", "filetwo")
-//
-// It's important to note this WILL OVERRIDE an env variable that already exists - consider the .env file to forcefilly set all vars.
-func Overload(filenames ...string) error {
-	return load(true, filenames...)
-}
-
 func load(overload bool, filenames ...string) error {
 	filenames = filenamesOrDefault(filenames)
 	for _, filename := range filenames {
@@ -128,82 +109,13 @@ func Read(filenames ...string) (map[string]string, error) {
 	return ReadWithLookup(nil, filenames...)
 }
 
-// Unmarshal reads an env file from a string, returning a map of keys and values.
-func Unmarshal(str string) (map[string]string, error) {
-	return UnmarshalBytes([]byte(str))
-}
-
-// UnmarshalBytes parses env file from byte slice of chars, returning a map of keys and values.
-func UnmarshalBytes(src []byte) (map[string]string, error) {
-	return UnmarshalBytesWithLookup(src, nil)
-}
-
 // UnmarshalBytesWithLookup parses env file from byte slice of chars, returning a map of keys and values.
 func UnmarshalBytesWithLookup(src []byte, lookupFn LookupFn) (map[string]string, error) {
 	out := make(map[string]string)
-	err := parseBytes(src, out, lookupFn)
+	err := newParser().parseBytes(src, out, lookupFn)
 	return out, err
 }
 
-// Exec loads env vars from the specified filenames (empty map falls back to default)
-// then executes the cmd specified.
-//
-// Simply hooks up os.Stdin/err/out to the command and calls Run()
-//
-// If you want more fine grained control over your command it's recommended
-// that you use `Load()` or `Read()` and the `os/exec` package yourself.
-//
-// Deprecated: Use the `os/exec` package directly.
-func Exec(filenames []string, cmd string, cmdArgs []string) error {
-	if err := Load(filenames...); err != nil {
-		return err
-	}
-
-	command := exec.Command(cmd, cmdArgs...)
-	command.Stdin = os.Stdin
-	command.Stdout = os.Stdout
-	command.Stderr = os.Stderr
-	return command.Run()
-}
-
-// Write serializes the given environment and writes it to a file
-//
-// Deprecated: The serialization functions are untested and unmaintained.
-func Write(envMap map[string]string, filename string) error {
-	//goland:noinspection GoDeprecation
-	content, err := Marshal(envMap)
-	if err != nil {
-		return err
-	}
-	file, err := os.Create(filename)
-	if err != nil {
-		return err
-	}
-	defer file.Close()
-	_, err = file.WriteString(content + "\n")
-	if err != nil {
-		return err
-	}
-	return file.Sync()
-}
-
-// Marshal outputs the given environment as a dotenv-formatted environment file.
-// Each line is in the format: KEY="VALUE" where VALUE is backslash-escaped.
-//
-// Deprecated: The serialization functions are untested and unmaintained.
-func Marshal(envMap map[string]string) (string, error) {
-	lines := make([]string, 0, len(envMap))
-	for k, v := range envMap {
-		if d, err := strconv.Atoi(v); err == nil {
-			lines = append(lines, fmt.Sprintf(`%s=%d`, k, d))
-		} else {
-			lines = append(lines, fmt.Sprintf(`%s="%s"`, k, doubleQuoteEscape(v))) // nolint // Cannot use %q here
-		}
-	}
-	sort.Strings(lines)
-	return strings.Join(lines, "\n"), nil
-}
-
 func filenamesOrDefault(filenames []string) []string {
 	if len(filenames) == 0 {
 		return []string{".env"}
@@ -255,19 +167,3 @@ func expandVariables(value string, envMap map[string]string, lookupFn LookupFn)
 	}
 	return retVal, nil
 }
-
-// Deprecated: only used by unsupported/untested code for Marshal/Write.
-func doubleQuoteEscape(line string) string {
-	const doubleQuoteSpecialChars = "\\\n\r\"!$`"
-	for _, c := range doubleQuoteSpecialChars {
-		toReplace := "\\" + string(c)
-		if c == '\n' {
-			toReplace = `\n`
-		}
-		if c == '\r' {
-			toReplace = `\r`
-		}
-		line = strings.ReplaceAll(line, string(c), toReplace)
-	}
-	return line
-}
diff --git a/dotenv/godotenv_test.go b/dotenv/godotenv_test.go
index 163941df..cee78c67 100644
--- a/dotenv/godotenv_test.go
+++ b/dotenv/godotenv_test.go
@@ -55,14 +55,6 @@ func TestLoadWithNoArgsLoadsDotEnv(t *testing.T) {
 	}
 }
 
-func TestOverloadWithNoArgsOverloadsDotEnv(t *testing.T) {
-	err := Overload()
-	pathError := err.(*os.PathError)
-	if pathError == nil || pathError.Op != "open" || pathError.Path != ".env" {
-		t.Errorf("Didn't try and open .env by default")
-	}
-}
-
 func TestLoadFileNotFound(t *testing.T) {
 	err := Load("somefilethatwillneverexistever.env")
 	if err == nil {
@@ -70,13 +62,6 @@ func TestLoadFileNotFound(t *testing.T) {
 	}
 }
 
-func TestOverloadFileNotFound(t *testing.T) {
-	err := Overload("somefilethatwillneverexistever.env")
-	if err == nil {
-		t.Error("File wasn't found but Overload didn't return an error")
-	}
-}
-
 func TestReadPlainEnv(t *testing.T) {
 	envFileName := "fixtures/plain.env"
 	expectedValues := map[string]string{
@@ -139,20 +124,6 @@ func TestLoadDoesNotOverride(t *testing.T) {
 	loadEnvAndCompareValues(t, Load, envFileName, expectedValues, presets)
 }
 
-func TestOverloadDoesOverride(t *testing.T) {
-	envFileName := "fixtures/plain.env"
-
-	// ensure NO overload
-	presets := map[string]string{
-		"OPTION_A": "do_not_override",
-	}
-
-	expectedValues := map[string]string{
-		"OPTION_A": "1",
-	}
-	loadEnvAndCompareValues(t, Overload, envFileName, expectedValues, presets)
-}
-
 func TestLoadPlainEnv(t *testing.T) {
 	envFileName := "fixtures/plain.env"
 	expectedValues := map[string]string{
@@ -494,7 +465,7 @@ func TestLinesToIgnore(t *testing.T) {
 
 	for n, c := range cases {
 		t.Run(n, func(t *testing.T) {
-			got := string(getStatementStart([]byte(c.input)))
+			got := string(newParser().getStatementStart([]byte(c.input)))
 			if got != c.want {
 				t.Errorf("Expected:\t %q\nGot:\t %q", c.want, got)
 			}
@@ -513,10 +484,8 @@ func TestErrorReadDirectory(t *testing.T) {
 
 func TestErrorParsing(t *testing.T) {
 	envFileName := "fixtures/invalid1.env"
-	envMap, err := Read(envFileName)
-	if err == nil {
-		t.Errorf("Expected error, got %v", envMap)
-	}
+	_, err := Read(envFileName)
+	assert.ErrorContains(t, err, "line 7: key cannot contain a space")
 }
 
 func TestInheritedEnvVariableSameSize(t *testing.T) {
diff --git a/dotenv/parser.go b/dotenv/parser.go
index 84347e31..e046619b 100644
--- a/dotenv/parser.go
+++ b/dotenv/parser.go
@@ -21,24 +21,34 @@ var (
 	exportRegex    = regexp.MustCompile(`^export\s+`)
 )
 
-func parseBytes(src []byte, out map[string]string, lookupFn LookupFn) error {
+type parser struct {
+	line int
+}
+
+func newParser() *parser {
+	return &parser{
+		line: 1,
+	}
+}
+
+func (p *parser) parseBytes(src []byte, out map[string]string, lookupFn LookupFn) error {
 	cutset := src
 	if lookupFn == nil {
 		lookupFn = noLookupFn
 	}
 	for {
-		cutset = getStatementStart(cutset)
+		cutset = p.getStatementStart(cutset)
 		if cutset == nil {
 			// reached end of file
 			break
 		}
 
-		key, left, inherited, err := locateKeyName(cutset)
+		key, left, inherited, err := p.locateKeyName(cutset)
 		if err != nil {
 			return err
 		}
 		if strings.Contains(key, " ") {
-			return errors.New("key cannot contain a space")
+			return fmt.Errorf("line %d: key cannot contain a space", p.line)
 		}
 
 		if inherited {
@@ -50,7 +60,7 @@ func parseBytes(src []byte, out map[string]string, lookupFn LookupFn) error {
 			continue
 		}
 
-		value, left, err := extractVarValue(left, out, lookupFn)
+		value, left, err := p.extractVarValue(left, out, lookupFn)
 		if err != nil {
 			return err
 		}
@@ -65,8 +75,8 @@ func parseBytes(src []byte, out map[string]string, lookupFn LookupFn) error {
 // getStatementPosition returns position of statement begin.
 //
 // It skips any comment line or non-whitespace character.
-func getStatementStart(src []byte) []byte {
-	pos := indexOfNonSpaceChar(src)
+func (p *parser) getStatementStart(src []byte) []byte {
+	pos := p.indexOfNonSpaceChar(src)
 	if pos == -1 {
 		return nil
 	}
@@ -81,12 +91,11 @@ func getStatementStart(src []byte) []byte {
 	if pos == -1 {
 		return nil
 	}
-
-	return getStatementStart(src[pos:])
+	return p.getStatementStart(src[pos:])
 }
 
 // locateKeyName locates and parses key name and returns rest of slice
-func locateKeyName(src []byte) (string, []byte, bool, error) {
+func (p *parser) locateKeyName(src []byte) (string, []byte, bool, error) {
 	var key string
 	var inherited bool
 	// trim "export" and space at beginning
@@ -116,8 +125,8 @@ loop:
 			}
 
 			return "", nil, inherited, fmt.Errorf(
-				`unexpected character %q in variable name near %q`,
-				string(char), string(src))
+				`line %d: unexpected character %q in variable name`,
+				p.line, string(char))
 		}
 	}
 
@@ -132,11 +141,12 @@ loop:
 }
 
 // extractVarValue extracts variable value and returns rest of slice
-func extractVarValue(src []byte, envMap map[string]string, lookupFn LookupFn) (string, []byte, error) {
+func (p *parser) extractVarValue(src []byte, envMap map[string]string, lookupFn LookupFn) (string, []byte, error) {
 	quote, isQuoted := hasQuotePrefix(src)
 	if !isQuoted {
 		// unquoted value - read until new line
 		value, rest, _ := bytes.Cut(src, []byte("\n"))
+		p.line++
 
 		// Remove inline comments on unquoted lines
 		value, _, _ = bytes.Cut(value, []byte(" #"))
@@ -147,6 +157,9 @@ func extractVarValue(src []byte, envMap map[string]string, lookupFn LookupFn) (s
 
 	// lookup quoted string terminator
 	for i := 1; i < len(src); i++ {
+		if src[i] == '\n' {
+			p.line++
+		}
 		if char := src[i]; char != quote {
 			continue
 		}
@@ -177,7 +190,7 @@ func extractVarValue(src []byte, envMap map[string]string, lookupFn LookupFn) (s
 		valEndIndex = len(src)
 	}
 
-	return "", nil, fmt.Errorf("unterminated quoted value %s", src[:valEndIndex])
+	return "", nil, fmt.Errorf("line %d: unterminated quoted value %s", p.line, src[:valEndIndex])
 }
 
 func expandEscapes(str string) string {
@@ -212,8 +225,11 @@ func expandEscapes(str string) string {
 	return out
 }
 
-func indexOfNonSpaceChar(src []byte) int {
+func (p *parser) indexOfNonSpaceChar(src []byte) int {
 	return bytes.IndexFunc(src, func(r rune) bool {
+		if r == '\n' {
+			p.line++
+		}
 		return !unicode.IsSpace(r)
 	})
 }
diff --git a/loader/loader.go b/loader/loader.go
index 64b691ba..6afa79fe 100644
--- a/loader/loader.go
+++ b/loader/loader.go
@@ -657,7 +657,7 @@ func resolveEnvironment(serviceConfig *types.ServiceConfig, workingDir string, l
 
 			fileVars, err := dotenv.ParseWithLookup(bytes.NewBuffer(b), resolve)
 			if err != nil {
-				return err
+				return errors.Wrapf(err, "Failed to load %s", filePath)
 			}
 			env := types.MappingWithEquals{}
 			for k, v := range fileVars {