diff --git a/core/jobs/playtime_entries.py b/core/jobs/playtime_entries.py
index 6e5917ed84..c9f72bc87f 100644
--- a/core/jobs/playtime_entries.py
+++ b/core/jobs/playtime_entries.py
@@ -132,12 +132,18 @@ def do_run(self):
             Configuration.REPORTING_NAME_ENVIRONMENT_VARIABLE, ""
         )
 
+        # format report name for use in csv attachment filename below
+        subject_prefix = reporting_name
         if len(reporting_name) > 0:
-            reporting_name += ": "
+            subject_prefix += ": "
 
-        email_subject = f"{reporting_name}Playtime Summaries {formatted_start_date} - {formatted_until_date}"
+        email_subject = f"{subject_prefix}Playtime Summaries {formatted_start_date} - {formatted_until_date}"
+        reporting_name_with_no_spaces = reporting_name.replace(" ", "_") + "-"
         attachment_extension = "csv"
-        attachment_name = f"playtime-summary-{formatted_start_date}-{formatted_until_date}.{attachment_extension}"
+        attachment_name = (
+            f"playtime-summary-{reporting_name_with_no_spaces}"
+            f"{formatted_start_date}-{formatted_until_date}.{attachment_extension}"
+        )
 
         # Write to a temporary file so we don't overflow the memory
         with TemporaryFile(
diff --git a/tests/core/jobs/test_playtime_entries.py b/tests/core/jobs/test_playtime_entries.py
index 438293e44c..b7bd95e8ab 100644
--- a/tests/core/jobs/test_playtime_entries.py
+++ b/tests/core/jobs/test_playtime_entries.py
@@ -247,7 +247,7 @@ def test_do_run(self, db: DatabaseTransactionFixture):
         # collection2 library2
         playtime(db.session, identifier, collection2, library2, date3m(3), 300)
 
-        reporting_name = "test-cm"
+        reporting_name = "test cm"
 
         # Horrible unbracketted syntax for python 3.8
         with patch("core.jobs.playtime_entries.csv.writer") as writer, patch(
@@ -297,7 +297,7 @@ def test_do_run(self, db: DatabaseTransactionFixture):
             receivers=["reporting@test.email"],
             text="",
             attachments={
-                f"playtime-summary-{cutoff}-{until}.csv": ""
+                f"playtime-summary-{reporting_name.replace(' ', '_')}-{cutoff}-{until}.csv": ""
             },  # Mock objects do not write data
         )