diff --git a/src/derivation/collector/keys_collector.rs b/src/derivation/collector/keys_collector.rs
index ae0093b4..bf842e8b 100644
--- a/src/derivation/collector/keys_collector.rs
+++ b/src/derivation/collector/keys_collector.rs
@@ -23,23 +23,23 @@ impl KeysCollector {
         all_factor_sources_in_profile: impl Into<IndexSet<HDFactorSource>>,
         interactors: Arc<dyn KeysCollectingInteractors>,
         preprocessor: KeysCollectorPreprocessor,
-    ) -> Self {
+    ) -> Result<Self> {
         let all_factor_sources_in_profile = all_factor_sources_in_profile.into();
-        let (state, factors) = preprocessor.preprocess(all_factor_sources_in_profile);
+        let (state, factors) = preprocessor.preprocess(all_factor_sources_in_profile)?;
 
         let dependencies = KeysCollectorDependencies::new(interactors, factors);
 
-        Self {
+        Ok(Self {
             dependencies,
             state: RefCell::new(state),
-        }
+        })
     }
 
     pub fn new(
         all_factor_sources_in_profile: IndexSet<HDFactorSource>,
         derivation_paths: IndexMap<FactorSourceIDFromHash, IndexSet<DerivationPath>>,
         interactors: Arc<dyn KeysCollectingInteractors>,
-    ) -> Self {
+    ) -> Result<Self> {
         let preprocessor = KeysCollectorPreprocessor::new(derivation_paths);
         Self::with_preprocessor(all_factor_sources_in_profile, interactors, preprocessor)
     }
diff --git a/src/derivation/collector/keys_collector_preprocessor.rs b/src/derivation/collector/keys_collector_preprocessor.rs
index c15dd664..1b191358 100644
--- a/src/derivation/collector/keys_collector_preprocessor.rs
+++ b/src/derivation/collector/keys_collector_preprocessor.rs
@@ -13,25 +13,27 @@ impl KeysCollectorPreprocessor {
     pub(crate) fn preprocess(
         &self,
         all_factor_sources_in_profile: IndexSet<HDFactorSource>,
-    ) -> (KeysCollectorState, IndexSet<FactorSourcesOfKind>) {
+    ) -> Result<(KeysCollectorState, IndexSet<FactorSourcesOfKind>)> {
         let all_factor_sources_in_profile = all_factor_sources_in_profile
             .into_iter()
             .map(|f| (f.factor_source_id(), f))
             .collect::<HashMap<FactorSourceIDFromHash, HDFactorSource>>();
 
-        let factor_sources_of_kind = sort_group_factors(
-            self.derivation_paths
-                .clone()
-                .keys()
-                .map(|id| {
-                    all_factor_sources_in_profile
-                        .get(id)
-                        .expect("Should have all factor sources")
-                        .clone()
-                })
-                .collect::<HashSet<_>>(),
-        );
+        let unsorted = self
+            .derivation_paths
+            .clone()
+            .keys()
+            .map(|id| {
+                all_factor_sources_in_profile
+                    .get(id)
+                    .cloned()
+                    .ok_or(CommonError::UnknownFactorSource)
+            })
+            .collect::<Result<HashSet<_>>>()?;
+
+        let factor_sources_of_kind = sort_group_factors(unsorted);
         let state = KeysCollectorState::new(self.derivation_paths.clone());
-        (state, factor_sources_of_kind)
+
+        Ok((state, factor_sources_of_kind))
     }
 }
diff --git a/src/testing/derivation/test_keys_collector.rs b/src/testing/derivation/test_keys_collector.rs
index 5e7e7a3d..73a5b6ce 100644
--- a/src/testing/derivation/test_keys_collector.rs
+++ b/src/testing/derivation/test_keys_collector.rs
@@ -158,6 +158,7 @@ impl KeysCollector {
             derivation_paths.into_iter().collect(),
             Arc::new(TestDerivationInteractors::default()),
         )
+        .unwrap()
     }
 
     pub fn new_test(
diff --git a/tests/main.rs b/tests/main.rs
index aec79a44..8a11d699 100644
--- a/tests/main.rs
+++ b/tests/main.rs
@@ -39,7 +39,25 @@ mod key_derivation_tests {
     use super::*;
 
     #[actix_rt::test]
-    async fn failure() {
+    async fn failure_unknown_factor() {
+        let res = KeysCollector::new(
+            IndexSet::new(),
+            IndexMap::from_iter([(
+                FactorSourceIDFromHash::fs0(),
+                IndexSet::from_iter([DerivationPath::new(
+                    Mainnet,
+                    Account,
+                    T9n,
+                    HDPathComponent::securified(0),
+                )]),
+            )]),
+            Arc::new(TestDerivationInteractors::default()),
+        );
+        assert!(matches!(res, Err(CommonError::UnknownFactorSource)));
+    }
+
+    #[actix_rt::test]
+    async fn failure_from_interactor() {
         let factor_source = fs_at(0);
         let paths = [0, 1, 2]
             .into_iter()
@@ -51,9 +69,9 @@ mod key_derivation_tests {
                 .into_iter()
                 .collect::<IndexMap<FactorSourceIDFromHash, IndexSet<DerivationPath>>>(),
             Arc::new(TestDerivationInteractors::fail()),
-        );
+        )
+        .unwrap();
         let outcome = collector.collect_keys().await;
-        println!("{:#?}", outcome);
         assert!(outcome.all_factors().is_empty())
     }