diff --git a/rslib/src/scheduler/fsrs/retention.rs b/rslib/src/scheduler/fsrs/retention.rs
index 4d9fbb3c2..b4b642654 100644
--- a/rslib/src/scheduler/fsrs/retention.rs
+++ b/rslib/src/scheduler/fsrs/retention.rs
@@ -174,10 +174,12 @@ impl Collection {
             }
             let mut arr = [0.0; 5];
             for (review_kind, group) in group_sec_by_review_kind.iter().enumerate() {
-                if group.is_empty() && review_kind == RevlogReviewKind::Relearning as usize {
-                    return Err(AnkiError::FsrsInsufficientData);
-                }
-                let average_secs = group.iter().sum::<u32>() as f64 / group.len() as f64 / 1000.0;
+                let average_secs =
+                    if group.is_empty() && review_kind == RevlogReviewKind::Relearning as usize {
+                        30.0
+                    } else {
+                        group.iter().sum::<u32>() as f64 / group.len() as f64 / 1000.0
+                    };
                 arr[review_kind] = average_secs
             }
             arr