diff --git a/pyproject.toml b/pyproject.toml
index 7473fa4..5fe8012 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -170,7 +170,7 @@ profile = "black"
 multi_line_output = 3
 indent = 4
 color_output = true
-known_third_party = ["Crypto", "PySide6", "coloredlogs", "dataclasses_json", "ffmpeg", "m3u8", "mpegdash", "mutagen", "pathvalidate", "requests", "rich", "tidalapi", "typer"]
+known_third_party = ["Crypto", "PySide6", "coloredlogs", "dataclasses_json", "ffmpeg", "helper", "m3u8", "mpegdash", "mutagen", "pathvalidate", "requests", "rich", "tidalapi", "typer"]
 
 [tool.mypy]
 # https://mypy.readthedocs.io/en/latest/config_file.html#using-a-pyproject-toml-file
diff --git a/tidal_dl_ng/dialog.py b/tidal_dl_ng/dialog.py
index b1901fd..34735a6 100644
--- a/tidal_dl_ng/dialog.py
+++ b/tidal_dl_ng/dialog.py
@@ -2,6 +2,7 @@ import os.path
 from enum import Enum
 from pathlib import Path
 
+from helper.path import is_installed_ffmpeg
 from PySide6 import QtCore, QtGui, QtWidgets
 from tidalapi import Quality as QualityAudio
 
@@ -86,19 +87,39 @@ class DialogPreferences(QtWidgets.QDialog):
         pixmapi: QtWidgets.QStyle.StandardPixmap = QtWidgets.QStyle.SP_MessageBoxQuestion
         self.icon = self.style().standardIcon(pixmapi)
 
-        self.parameters_checkboxes = [
-            "lyrics_embed",
-            "lyrics_file",
-            "video_download",
-            "download_delay",
-            "video_convert_mp4",
-        ]
-        self.parameters_combo = [
-            ("skip_existing", SkipExisting),
-            ("quality_audio", QualityAudio),
-            ("quality_video", QualityVideo),
-            ("metadata_cover_dimension", CoverDimensions),
-        ]
+        self._init_checkboxes()
+        self._init_comboboxes()
+        self._init_line_edit()
+
+        # Create an instance of the GUI
+        self.ui = Ui_DialogSettings()
+
+        # Run the .setupUi() method to show the GUI
+        self.ui.setupUi(self)
+        # Set data.
+        self.gui_populate()
+        self._init_signals()
+
+        self.exec()
+
+    def _init_signals(self):
+        self.ui.cb_video_convert_mp4.stateChanged.connect(self.on_cb_video_convert_mp4)
+
+    def on_cb_video_convert_mp4(self, int):
+        if self.ui.cb_video_convert_mp4.isChecked():
+            # Check if ffmpeg is in PATH otherwise show error message.
+            if not is_installed_ffmpeg():
+                self.ui.cb_video_convert_mp4.setChecked(False)
+                self.ui.cb_video_convert_mp4.setCheckState(QtCore.Qt.CheckState.Unchecked)
+                QtWidgets.QMessageBox.critical(
+                    self,
+                    "FFmpeg not found!",
+                    "Either FFmpeg is not installed on your computer or not set within "
+                    "your PATH variable. You cannot activate this option until FFmpeg "
+                    "is correctly installed and set to your environmental PATH variable.",
+                )
+
+    def _init_line_edit(self):
         self.parameters_line_edit = [
             "download_base_path",
             "format_album",
@@ -108,15 +129,22 @@ class DialogPreferences(QtWidgets.QDialog):
             "format_video",
         ]
 
-        # Create an instance of the GUI
-        self.ui = Ui_DialogSettings()
+    def _init_comboboxes(self):
+        self.parameters_combo = [
+            ("skip_existing", SkipExisting),
+            ("quality_audio", QualityAudio),
+            ("quality_video", QualityVideo),
+            ("metadata_cover_dimension", CoverDimensions),
+        ]
 
-        # Run the .setupUi() method to show the GUI
-        self.ui.setupUi(self)
-        # Set data.
-        self.gui_populate()
-
-        self.exec()
+    def _init_checkboxes(self):
+        self.parameters_checkboxes = [
+            "lyrics_embed",
+            "lyrics_file",
+            "video_download",
+            "download_delay",
+            "video_convert_mp4",
+        ]
 
     def gui_populate(self):
         self.populate_checkboxes()
@@ -190,7 +218,7 @@ class DialogPreferences(QtWidgets.QDialog):
             checkbox.setChecked(getattr(self.data, pn))
 
     def accept(self):
-        # Get settings. TODO
+        # Get settings.
         self.to_settings()
         self.done(1)
 
diff --git a/tidal_dl_ng/download.py b/tidal_dl_ng/download.py
index 1ca62e5..2afdf20 100644
--- a/tidal_dl_ng/download.py
+++ b/tidal_dl_ng/download.py
@@ -29,7 +29,7 @@ from tidal_dl_ng.constants import (
 )
 from tidal_dl_ng.helper.decryption import decrypt_file, decrypt_security_token
 from tidal_dl_ng.helper.exceptions import MediaMissing, UnknownManifestFormat
-from tidal_dl_ng.helper.path import check_file_exists, format_path_media, path_file_sanitize
+from tidal_dl_ng.helper.path import check_file_exists, format_path_media, is_installed_ffmpeg, path_file_sanitize
 from tidal_dl_ng.helper.tidal import (
     instantiate_media,
     items_results_all,
@@ -82,6 +82,13 @@ class Download:
         self.progress = progress
         self.path_base = path_base
 
+        if not is_installed_ffmpeg() and self.settings.data.video_convert_mp4:
+            self.settings.data.video_convert_mp4 = False
+            self.fn_logger.error(
+                "Cannot find FFmpeg in PATH. Videos can be downloaded but will not be processed. "
+                "Make sure FFmpeg is installed correctly and present within your environmental PATH variable."
+            )
+
     def _download(
         self,
         media: Track | Video,
diff --git a/tidal_dl_ng/helper/path.py b/tidal_dl_ng/helper/path.py
index 43dd9de..2b739d6 100644
--- a/tidal_dl_ng/helper/path.py
+++ b/tidal_dl_ng/helper/path.py
@@ -2,6 +2,7 @@ import glob
 import math
 import os
 import re
+import shutil
 from pathlib import Path, PosixPath
 
 from pathvalidate import sanitize_filename, sanitize_filepath
@@ -261,3 +262,10 @@ def check_file_exists(path_file: str, extension_ignore: bool = False) -> bool:
     result = bool(sum([glob.glob(_file) for _file in path_files], []))
 
     return result
+
+
+def is_installed_ffmpeg() -> bool:
+    # Checks if ffmpeg is found in PATH.
+    result: bool = bool(shutil.which("ffmpeg"))
+
+    return result