diff --git a/templates/zerver/slack_import.html b/templates/zerver/slack_import.html
index e3bf5b57e9..f9e7dd2e0e 100644
--- a/templates/zerver/slack_import.html
+++ b/templates/zerver/slack_import.html
@@ -70,7 +70,7 @@
                         {% endtrans %}
                     </div>
                     <div id="slack-import-drag-and-drop" data-max-file-size="{{max_file_size}}"></div>
-                    <p id="slack-import-file-upload-error" class="help-inline text-error"></p>
+                    <p id="slack-import-file-upload-error" class="help-inline text-error">{{ invalid_file_error_message }}</p>
                 </div>
                 <form id="slack-import-start-upload-wrapper" method="post" class="form-inline {% if uploaded_import_file_name %}{% else %}hidden{% endif %}" action="{{ url('import_realm_from_slack') }}">
                     {{ csrf_input }}
diff --git a/zerver/actions/data_import.py b/zerver/actions/data_import.py
index e25577046f..61518db802 100644
--- a/zerver/actions/data_import.py
+++ b/zerver/actions/data_import.py
@@ -10,6 +10,7 @@ from zerver.actions.realm_settings import do_delete_all_realm_attachments
 from zerver.actions.users import do_change_user_role
 from zerver.context_processors import is_realm_import_enabled
 from zerver.data_import.slack import do_convert_zipfile
+from zerver.lib.exceptions import SlackImportInvalidFileError
 from zerver.lib.import_realm import do_import_realm
 from zerver.lib.upload import save_attachment_contents
 from zerver.models.prereg_users import PreregistrationRealm
@@ -78,6 +79,9 @@ def import_slack_data(event: dict[str, Any]) -> None:
             # Clean up the realm if the import failed
             preregistration_realm.created_realm = None
             preregistration_realm.data_import_metadata["is_import_work_queued"] = False
+            if type(e) is SlackImportInvalidFileError:
+                # Store the error to be displayed to the user.
+                preregistration_realm.data_import_metadata["invalid_file_error_message"] = str(e)
             preregistration_realm.save()
 
             realm = Realm.objects.get(string_id=string_id)
diff --git a/zerver/data_import/slack.py b/zerver/data_import/slack.py
index 6f187bb8c5..b4774e0329 100644
--- a/zerver/data_import/slack.py
+++ b/zerver/data_import/slack.py
@@ -49,6 +49,7 @@ from zerver.data_import.slack_message_conversion import (
     process_slack_block_and_attachment,
 )
 from zerver.lib.emoji import codepoint_to_name, get_emoji_file_name
+from zerver.lib.exceptions import SlackImportInvalidFileError
 from zerver.lib.export import MESSAGE_BATCH_CHUNK_SIZE, do_common_export_processes
 from zerver.lib.mime_types import guess_type
 from zerver.lib.storage import static_path
@@ -1523,7 +1524,9 @@ def do_convert_zipfile(
                 # top-level directories, or as `canvas_in_the_conversation.json`
                 # files in channel directories.  We do not parse these currently.
                 if not re.match(r"[^/]+(\.json|/([^/]+\.json)?)$", fileinfo.filename):
-                    raise Exception("This zip file does not look like a Slack archive")
+                    raise SlackImportInvalidFileError(
+                        "Uploaded zip file is not a valid Slack export."
+                    )
 
                 # file_size is the uncompressed size of the file
                 total_size += fileinfo.file_size
@@ -1532,7 +1535,7 @@ def do_convert_zipfile(
             # than a 10x size magnification is suspect, particularly
             # if it results in over 1GB.
             if total_size > 1024 * 1024 * 1024 and total_size > 10 * os.path.getsize(original_path):
-                raise Exception("This zip file is possibly malicious")
+                raise SlackImportInvalidFileError("Uploaded zip file is not a valid Slack export.")
 
             zipObj.extractall(slack_data_dir)
 
diff --git a/zerver/lib/exceptions.py b/zerver/lib/exceptions.py
index a0a0b654f6..ff019bc3d4 100644
--- a/zerver/lib/exceptions.py
+++ b/zerver/lib/exceptions.py
@@ -776,3 +776,14 @@ class DeliveryTimeNotInFutureError(JsonableError):
     @override
     def msg_format() -> str:
         return _("Scheduled delivery time must be in the future.")
+
+
+class SlackImportInvalidFileError(Exception):
+    """
+    An error that is raised during the Slack import process
+    and is intended to be shown to the user.
+    """
+
+    def __init__(self, message: str) -> None:
+        super().__init__(message)
+        self.message = message
diff --git a/zerver/tests/test_slack_importer.py b/zerver/tests/test_slack_importer.py
index 35e7e3444b..834387887a 100644
--- a/zerver/tests/test_slack_importer.py
+++ b/zerver/tests/test_slack_importer.py
@@ -52,6 +52,7 @@ from zerver.data_import.slack import (
     slack_workspace_to_realm,
     users_to_zerver_userprofile,
 )
+from zerver.lib.exceptions import SlackImportInvalidFileError
 from zerver.lib.import_realm import do_import_realm
 from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.test_helpers import find_key_by_email, read_test_image_file
@@ -2255,7 +2256,7 @@ by Pieter
             email="test@example.com",
             data_import_metadata={"import_from": "slack"},
         )
-        mock_do_import_realm.side_effect = AssertionError("Import failed")
+        mock_do_import_realm.side_effect = SlackImportInvalidFileError("Invalid file")
 
         event = {
             "preregistration_realm_id": prereg_realm.id,
@@ -2264,7 +2265,7 @@ by Pieter
         }
 
         with (
-            self.assertRaises(AssertionError),
+            self.assertRaises(SlackImportInvalidFileError),
             self.assertLogs("zerver.actions.data_import", "ERROR"),
         ):
             import_slack_data(event)
@@ -2272,6 +2273,9 @@ by Pieter
         prereg_realm.refresh_from_db()
         self.assertIsNone(prereg_realm.created_realm)
         self.assertFalse(prereg_realm.data_import_metadata["is_import_work_queued"])
+        self.assertEqual(
+            prereg_realm.data_import_metadata["invalid_file_error_message"], "Invalid file"
+        )
         self.assertFalse(Realm.objects.filter(string_id="test-realm").exists())
 
     @mock.patch("zerver.actions.data_import.do_import_realm")
diff --git a/zerver/views/registration.py b/zerver/views/registration.py
index 66e71027e7..01f64ec292 100644
--- a/zerver/views/registration.py
+++ b/zerver/views/registration.py
@@ -390,6 +390,9 @@ def registration_helper(
                 context["uploaded_import_file_name"] = prereg_realm.data_import_metadata.get(
                     "uploaded_import_file_name"
                 )
+                context["invalid_file_error_message"] = prereg_realm.data_import_metadata.get(
+                    "invalid_file_error_message", ""
+                )
 
             return TemplateResponse(
                 request,
@@ -1055,7 +1058,22 @@ def realm_import_status(
         # TODO: Either store the path to the temporary conversion directory on
         # preregistration_realm.data_import_metadata, or have the conversion
         # process support writing updates to this for a better progress indicator.
-        return json_success(request, {"status": _("Converting Slack data… This may take a while.")})
+        if preregistration_realm.data_import_metadata.get("is_import_work_queued"):
+            return json_success(
+                request, {"status": _("Converting Slack data… This may take a while.")}
+            )
+        elif preregistration_realm.data_import_metadata.get("invalid_file_error_message"):
+            # Redirect user the file upload page if we have an error message to display.
+            result = {
+                "status": preregistration_realm.data_import_metadata.get(
+                    "invalid_file_error_message"
+                ),
+                "redirect": reverse(
+                    "get_prereg_key_and_redirect", kwargs={"confirmation_key": confirmation_key}
+                ),
+            }
+            return json_success(request, result)
+        # TODO: If there is something we need to fix for the import, we should notify the user.
 
     if realm.deactivated:
         # These "if" cases are in the inverse order than they're done