diff --git a/dangerzone/logic.py b/dangerzone/logic.py
index 21182a9..37e3380 100644
--- a/dangerzone/logic.py
+++ b/dangerzone/logic.py
@@ -65,11 +65,17 @@ class DangerzoneCore(object):
         self, ocr_lang: Optional[str], stdout_callback: Optional[Callable] = None
     ) -> None:
         def convert_doc(document: Document) -> None:
-            self.isolation_provider.convert(
-                document,
-                ocr_lang,
-                stdout_callback,
-            )
+            try:
+                self.isolation_provider.convert(
+                    document,
+                    ocr_lang,
+                    stdout_callback,
+                )
+            except Exception as e:
+                log.exception(
+                    f"Unexpected error occurred while converting '{document}'"
+                )
+                document.mark_as_failed()
 
         max_jobs = self.isolation_provider.get_max_parallel_conversions()
         with concurrent.futures.ThreadPoolExecutor(max_workers=max_jobs) as executor:
diff --git a/tests/test_cli.py b/tests/test_cli.py
index e9e9eda..f79a8cf 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -19,6 +19,7 @@ from strip_ansi import strip_ansi
 from dangerzone.cli import cli_main, display_banner
 from dangerzone.document import ARCHIVE_SUBDIR, SAFE_EXTENSION
 from dangerzone.isolation_provider.qubes import is_qubes_native_conversion
+from dangerzone.util import get_resource_path
 
 from .conftest import for_each_doc, for_each_external_doc
 
@@ -219,6 +220,20 @@ class TestCliConversion(TestCliBasic):
         result = self.run_cli([sample_pdf, "--output-filename", output_filename])
         result.assert_success()
 
+    ### Test method for swallowed exception
+    def test_output_filename_same_file_dummy_fails(self) -> None:
+        resource_path = get_resource_path("dummy_document.pdf")
+        # Using the same filename for both input and output should fail.
+        result = self.run_cli(
+            [
+                resource_path,
+                "--output-filename",
+                resource_path,
+                "--unsafe-dummy-conversion",
+            ]
+        )
+        result.assert_failure()
+
     def test_output_filename_new_dir(self, sample_pdf: str) -> None:
         output_filename = str(Path("fake-directory") / "my-output.pdf")
         result = self.run_cli([sample_pdf, "--output-filename", output_filename])