diff --git a/build.spec b/build.spec
index 2b83630..b2a6aa0 100644
--- a/build.spec
+++ b/build.spec
@@ -9,22 +9,31 @@ SELF_PATH = str(Path(".").absolute())
 if SELF_PATH not in sys.path:
     sys.path.insert(0, SELF_PATH)
 
-from constants import WORKING_DIR, DEFAULT_LANG
+from constants import WORKING_DIR, SITE_PACKAGES_PATH, DEFAULT_LANG
 
 if TYPE_CHECKING:
     from PyInstaller.building.api import PYZ, EXE
     from PyInstaller.building.build_main import Analysis
 
-
-datas: list[tuple[str | Path, str]] = [
-    ("pickaxe.ico", '.'),  # icon file
+# (source_path, dest_path, required)
+to_add: list[tuple[Path, str, bool]] = [
+    (Path("pickaxe.ico"), '.', True),  # icon file
     # SeleniumWire HTTPS/SSL cert file and key
-    ("./env/Lib/site-packages/seleniumwire/ca.crt", "./seleniumwire"),
-    ("./env/Lib/site-packages/seleniumwire/ca.key", "./seleniumwire"),
+    (Path(SITE_PACKAGES_PATH, "seleniumwire/ca.crt"), "./seleniumwire", False),
+    (Path(SITE_PACKAGES_PATH, "seleniumwire/ca.key"), "./seleniumwire", False),
 ]
 for lang_filepath in WORKING_DIR.joinpath("lang").glob("*.json"):
     if lang_filepath.stem != DEFAULT_LANG:
-        datas.append((lang_filepath, "lang"))
+        to_add.append((lang_filepath, "lang", True))
+
+# ensure the required to-be-added data exists
+datas: list[tuple[Path, str]] = []
+for source_path, dest_path, required in to_add:
+    if source_path.exists():
+        datas.append((source_path, dest_path))
+    elif required:
+        raise FileNotFoundError(str(source_path))
+
 
 block_cipher = None
 a = Analysis(
@@ -41,6 +50,7 @@ a = Analysis(
         "setuptools._distutils.dir_util",
         "setuptools._distutils.file_util",
         "setuptools._distutils.archive_util",
+        "PIL._tkinter_finder",
     ],
     runtime_hooks=[],
     cipher=block_cipher,
diff --git a/constants.py b/constants.py
index 98ccd04..17b6e33 100644
--- a/constants.py
+++ b/constants.py
@@ -22,6 +22,14 @@ IS_PACKAGED = hasattr(sys, "_MEIPASS")
 # logging special levels
 CALL = logging.INFO - 1
 logging.addLevelName(CALL, "CALL")
+# site-packages venv path changes depending on the system platform
+if sys.platform == "win32":
+    SYS_SITE_PACKAGES = "Lib/site-packages"
+else:
+    # On Linux, the site-packages path includes a versioned 'pythonX.Y' folder part
+    # The Lib folder is also spelled in lowercase: 'lib'
+    version_info = sys.version_info
+    SYS_SITE_PACKAGES = f"lib/python{version_info.major}.{version_info.minor}/site-packages"
 
 
 def _resource_path(relative_path: Path | str) -> Path:
@@ -46,6 +54,9 @@ SELF_PATH = Path(sys.argv[0]).absolute()
 if SELF_PATH.stem == "pyinstaller":
     SELF_PATH = Path(__file__).with_name("main.py").absolute()
 WORKING_DIR = SELF_PATH.absolute().parent
+# Development paths
+VENV_PATH = Path(WORKING_DIR, "env")
+SITE_PACKAGES_PATH = Path(VENV_PATH, SYS_SITE_PACKAGES)
 # Translations path
 # NOTE: These don't have to be available to the end-user, so the path points to the internal dir
 LANG_PATH = _resource_path("lang")