diff --git a/README.md b/README.md
index 14bb7ac..080be0b 100644
--- a/README.md
+++ b/README.md
@@ -95,7 +95,7 @@ fn main() -> Result<(), db_type::Error> {
     let retrieve_data: Item = r.get().primary(3_u32)?.unwrap();
     println!("data id='3': {:?}", retrieve_data);
     // Iterate items with name starting with "red"
-    for item in r.scan().secondary::<Item>(ItemKey::name)?.start_with("red") {
+    for item in r.scan().secondary::<Item>(ItemKey::name)?.start_with("red")? {
         println!("data name=\"red\": {:?}", item);
     }
     
diff --git a/benches/overhead_data_size.rs b/benches/overhead_data_size.rs
index 541ee8b..b8185ba 100644
--- a/benches/overhead_data_size.rs
+++ b/benches/overhead_data_size.rs
@@ -134,7 +134,7 @@ fn use_native_db_insert(db: &Database, data: Data) {
 
 fn use_native_db_scan(db: &Database) -> Vec<Data> {
     let r = db.r_transaction().unwrap();
-    let out = r.scan().primary().unwrap().all().try_collect().unwrap();
+    let out = r.scan().primary().unwrap().all().unwrap().try_collect().unwrap();
     out
 }
 
diff --git a/src/transaction/query/scan/primary_scan.rs b/src/transaction/query/scan/primary_scan.rs
index d04aa79..2366b5c 100644
--- a/src/transaction/query/scan/primary_scan.rs
+++ b/src/transaction/query/scan/primary_scan.rs
@@ -49,16 +49,16 @@ where
     ///     let r = db.r_transaction()?;
     ///     
     ///     // Get all values
-    ///     let _values: Vec<Data> = r.scan().primary()?.all().try_collect()?;
+    ///     let _values: Vec<Data> = r.scan().primary()?.all().unwrap().try_collect()?;
     ///     Ok(())
     /// }
     /// ```
-    pub fn all(&self) -> PrimaryScanIterator<T> {
-        let range = self.primary_table.range::<Key>(..).unwrap();
-        PrimaryScanIterator {
+    pub fn all(&self) -> Result<PrimaryScanIterator<T>> {
+        let range = self.primary_table.range::<Key>(..)?;
+        Ok(PrimaryScanIterator {
             range,
             _marker: PhantomData::default(),
-        }
+        })
     }
 
     /// Iterate over all values in a range.
@@ -87,20 +87,19 @@ where
     ///     let r = db.r_transaction()?;
     ///     
     ///     // Get the values from 5 to the end
-    ///     let _values: Vec<Data> = r.scan().primary()?.range(5u64..).try_collect()?;
+    ///     let _values: Vec<Data> = r.scan().primary()?.range(5u64..)?.try_collect()?;
     ///     Ok(())
     /// }
     /// ```
-    pub fn range<TR: ToKey, R: RangeBounds<TR>>(&self, range: R) -> PrimaryScanIterator<T> {
+    pub fn range<TR: ToKey, R: RangeBounds<TR>>(&self, range: R) -> Result<PrimaryScanIterator<T>> {
         let database_inner_key_value_range = KeyRange::new(range);
         let range = self
             .primary_table
-            .range::<Key>(database_inner_key_value_range)
-            .unwrap();
-        PrimaryScanIterator {
+            .range::<Key>(database_inner_key_value_range)?;
+        Ok(PrimaryScanIterator {
             range,
             _marker: PhantomData::default(),
-        }
+        })
     }
 
     /// Iterate over all values starting with a prefix.
@@ -129,24 +128,24 @@ where
     ///     let r = db.r_transaction()?;
     ///     
     ///     // Get the values starting with "victor"
-    ///     let _values: Vec<Data> = r.scan().primary()?.start_with("victor").try_collect()?;
+    ///     let _values: Vec<Data> = r.scan().primary()?.start_with("victor")?.try_collect()?;
     ///     Ok(())
     /// }
     /// ```
     pub fn start_with<'a>(
         &'a self,
         start_with: impl ToKey + 'a,
-    ) -> PrimaryScanIteratorStartWith<'a, T> {
+    ) -> Result<PrimaryScanIteratorStartWith<'a, T>> {
         let start_with = start_with.to_key();
         let range = self
             .primary_table
-            .range::<Key>(start_with.clone()..)
-            .unwrap();
-        PrimaryScanIteratorStartWith {
-            start_with,
+            .range::<Key>(start_with.clone()..)?;
+
+        Ok(PrimaryScanIteratorStartWith {
             range,
+            start_with,
             _marker: PhantomData::default(),
-        }
+        })
     }
 }
 
diff --git a/src/transaction/query/scan/secondary_scan.rs b/src/transaction/query/scan/secondary_scan.rs
index fdfc5c0..b9e26d2 100644
--- a/src/transaction/query/scan/secondary_scan.rs
+++ b/src/transaction/query/scan/secondary_scan.rs
@@ -61,31 +61,25 @@ where
     ///     let r = db.r_transaction()?;
     ///     
     ///     // Get only values that have the secondary key set (name is not None)
-    ///     let _values: Vec<Data> = r.scan().secondary(DataKey::name)?.all().try_collect()?;
+    ///     let _values: Vec<Data> = r.scan().secondary(DataKey::name)?.all().unwrap().try_collect()?;
     ///     Ok(())
     /// }
     /// ```
-    /// TODO: remove unwrap and return Result
-    pub fn all(&self) -> SecondaryScanIterator<PrimaryTable, T> {
+    pub fn all(&self) -> Result<SecondaryScanIterator<PrimaryTable, T>> {
         let mut primary_keys = vec![];
-        for keys in self.secondary_table.iter().unwrap() {
-            let (l_secondary_key, l_primary_keys) = keys.unwrap();
-            dbg!(&l_secondary_key.value());
+        for keys in self.secondary_table.iter()? {
+            let (_, l_primary_keys) = keys?;
             for primary_key in l_primary_keys {
-                let primary_key = primary_key.unwrap();
+                let primary_key = primary_key?;
                 primary_keys.push(primary_key);
             }
         }
 
-        for primary_key in primary_keys.iter() {
-            dbg!(&primary_key.value());
-        }
-
-        SecondaryScanIterator {
+        Ok(SecondaryScanIterator {
             primary_table: &self.primary_table,
             primary_keys: primary_keys.into_iter(),
             _marker: PhantomData::default(),
-        }
+        })
     }
 
     /// Iterate over all values by secondary key.
@@ -118,20 +112,19 @@ where
     ///     let r = db.r_transaction()?;
     ///     
     ///     // Get only values that have the secondary key name from C to the end
-    ///     let _values: Vec<Data> = r.scan().secondary(DataKey::name)?.range("C"..).try_collect()?;
+    ///     let _values: Vec<Data> = r.scan().secondary(DataKey::name)?.range("C"..).unwrap().try_collect()?;
     ///     Ok(())
     /// }
     /// ```
     pub fn range<TR: ToKey, R: RangeBounds<TR>>(
         &self,
         range: R,
-    ) -> SecondaryScanIterator<PrimaryTable, T> {
+    ) -> Result<SecondaryScanIterator<PrimaryTable, T>> {
         let mut primary_keys = vec![];
         let database_inner_key_value_range = KeyRange::new(range);
         for keys in self
             .secondary_table
-            .range::<Key>(database_inner_key_value_range)
-            .unwrap()
+            .range::<Key>(database_inner_key_value_range)?
         {
             let (_, l_primary_keys) = keys.unwrap();
             for primary_key in l_primary_keys {
@@ -140,11 +133,11 @@ where
             }
         }
 
-        SecondaryScanIterator {
+        Ok(SecondaryScanIterator {
             primary_table: &self.primary_table,
             primary_keys: primary_keys.into_iter(),
             _marker: PhantomData::default(),
-        }
+        })
     }
 
     /// Iterate over all values by secondary key.
@@ -177,20 +170,19 @@ where
     ///     let r = db.r_transaction()?;
     ///     
     ///     // Get only values that have the secondary key name starting with "hello"
-    ///     let _values: Vec<Data> = r.scan().secondary(DataKey::name)?.start_with("hello").try_collect()?;
+    ///     let _values: Vec<Data> = r.scan().secondary(DataKey::name)?.start_with("hello").unwrap().try_collect()?;
     ///     Ok(())
     /// }
     /// ```
     pub fn start_with<'a>(
         &'a self,
         start_with: impl ToKey + 'a,
-    ) -> SecondaryScanIterator<'a, PrimaryTable, T> {
+    ) -> Result<SecondaryScanIterator<'a, PrimaryTable, T>> {
         let start_with = start_with.to_key();
         let mut primary_keys = vec![];
         for keys in self
             .secondary_table
-            .range::<Key>(start_with.clone()..)
-            .unwrap()
+            .range::<Key>(start_with.clone()..)?
         {
             let (l_secondary_key, l_primary_keys) = keys.unwrap();
             if !l_secondary_key
@@ -206,11 +198,11 @@ where
             }
         }
 
-        SecondaryScanIterator {
+        Ok(SecondaryScanIterator {
             primary_table: &self.primary_table,
             primary_keys: primary_keys.into_iter(),
             _marker: PhantomData::default(),
-        }
+        })
     }
 }
 
diff --git a/src/transaction/rw_transaction.rs b/src/transaction/rw_transaction.rs
index 59a526a..9308fc6 100644
--- a/src/transaction/rw_transaction.rs
+++ b/src/transaction/rw_transaction.rs
@@ -283,7 +283,7 @@ impl<'db, 'txn> RwTransaction<'db> {
         OldType: ToInput + Clone,
         NewType: ToInput + From<OldType>,
     {
-        let find_all_old: Result<Vec<OldType>> = self.scan().primary()?.all().collect();
+        let find_all_old: Result<Vec<OldType>> = self.scan().primary()?.all()?.collect();
         let find_all_old = find_all_old?;
         for old in find_all_old {
             let new: NewType = old.clone().into();
diff --git a/tests/deserialization_error.rs b/tests/deserialization_error.rs
index 1bd2964..7fd8377 100644
--- a/tests/deserialization_error.rs
+++ b/tests/deserialization_error.rs
@@ -33,7 +33,7 @@ fn create_local_database_for_tests() {
     models.define::<Item1>().unwrap();
     let db = Builder::new().open(&models, &database_path).unwrap();
     let r = db.r_transaction().unwrap();
-    let result: Result<Vec<Item1>> = r.scan().primary().unwrap().all().try_collect();
+    let result: Result<Vec<Item1>> = r.scan().primary().unwrap().all().unwrap().try_collect();
     assert!(matches!(
         result,
         Err(Error::ModelError(ModelError::DecodeBodyError(_)))
diff --git a/tests/migrate/with_secondary_keys.rs b/tests/migrate/with_secondary_keys.rs
index 40d88b9..2e05b1d 100644
--- a/tests/migrate/with_secondary_keys.rs
+++ b/tests/migrate/with_secondary_keys.rs
@@ -165,7 +165,7 @@ fn test_migrate() {
         .secondary(ItemV2Key::first_name_key)
         .unwrap()
         .start_with("Alexandre")
-        .try_collect()
+        .unwrap().try_collect()
         .unwrap();
     assert_eq!(
         item,
@@ -182,7 +182,7 @@ fn test_migrate() {
         .secondary(ItemV2Key::last_name_key)
         .unwrap()
         .start_with("Verne")
-        .try_collect()
+        .unwrap().try_collect()
         .unwrap();
     assert_eq!(
         item,
diff --git a/tests/scan.rs b/tests/scan.rs
index ded1341..b3dc097 100644
--- a/tests/scan.rs
+++ b/tests/scan.rs
@@ -52,7 +52,7 @@ fn test_iter() {
     rw.commit().unwrap();
 
     let r = db.r_transaction().unwrap();
-    let result: Vec<Item> = r.scan().primary().unwrap().all().try_collect().unwrap();
+    let result: Vec<Item> = r.scan().primary().unwrap().all().unwrap().try_collect().unwrap();
     assert_eq!(result.len(), 2);
 
     let obj1 = result.get(0).unwrap();
@@ -85,7 +85,7 @@ fn test_iter_many_items_to_be_bytes() {
 
     let r = db.r_transaction().unwrap();
     {
-        let iter: Vec<Item> = r.scan().primary().unwrap().all().try_collect().unwrap();
+        let iter: Vec<Item> = r.scan().primary().unwrap().all().unwrap().try_collect().unwrap();
         assert_eq!(iter.len(), 257);
 
         let obj1 = iter.get(0).unwrap();
@@ -119,7 +119,7 @@ fn test_double_ended_iter() {
 
     let r = db.r_transaction().unwrap();
     let scan = r.scan().primary().unwrap();
-    let iter = scan.all();
+    let iter = scan.all().unwrap();
     let result: Vec<Item> = iter.rev().try_collect().unwrap();
 
     assert_eq!(result.len(), 2);
@@ -156,7 +156,7 @@ fn test_iter_range() {
         .primary()
         .unwrap()
         .range(..2_i32)
-        .try_collect()
+        .unwrap().try_collect()
         .unwrap();
     assert_eq!(result.len(), 1);
 
@@ -169,7 +169,7 @@ fn test_iter_range() {
         .primary()
         .unwrap()
         .range(2_i32..)
-        .try_collect()
+        .unwrap().try_collect()
         .unwrap();
     assert_eq!(result.len(), 2);
 
@@ -186,7 +186,7 @@ fn test_iter_range() {
         .primary()
         .unwrap()
         .range(2_i32..3_i32)
-        .try_collect()
+        .unwrap().try_collect()
         .unwrap();
     assert_eq!(result.len(), 1);
 
@@ -216,7 +216,7 @@ fn test_iter_by_key() {
         .secondary(ItemKey::secondary_key_1)
         .unwrap()
         .all()
-        .try_collect()
+        .unwrap().try_collect()
         .unwrap();
 
     assert_eq!(result.len(), 2);
@@ -247,7 +247,7 @@ fn test_double_ended_iter_by_key() {
 
     let r = db.r_transaction().unwrap();
     let scan = r.scan().secondary(ItemKey::secondary_key_1).unwrap();
-    let iter = scan.all();
+    let iter = scan.all().unwrap();
     let result: Vec<Item> = iter.rev().try_collect().unwrap();
 
     assert_eq!(result.len(), 2);
@@ -279,7 +279,7 @@ fn test_double_ended_iter_by_key_range() {
 
     let r = db.r_transaction().unwrap();
     let scan = r.scan().secondary(ItemKey::secondary_key_1).unwrap();
-    let iter = scan.range(..b"2".as_slice());
+    let iter = scan.range(..b"2".as_slice()).unwrap();
     let result: Vec<Item> = iter.rev().try_collect().unwrap();
 
     assert_eq!(result.len(), 1);
@@ -289,7 +289,7 @@ fn test_double_ended_iter_by_key_range() {
     assert_eq!(obj1.name, "test");
 
     let scan = r.scan().secondary(ItemKey::secondary_key_1).unwrap();
-    let iter = scan.range(b"2".as_slice()..);
+    let iter = scan.range(b"2".as_slice()..).unwrap();
     let result: Vec<Item> = iter.rev().try_collect().unwrap();
     assert_eq!(result.len(), 2);
 
@@ -302,7 +302,7 @@ fn test_double_ended_iter_by_key_range() {
     assert_eq!(obj2.name, "test2");
 
     let scan = r.scan().secondary(ItemKey::secondary_key_1).unwrap();
-    let iter = scan.range(b"2".as_slice()..b"3".as_slice());
+    let iter = scan.range(b"2".as_slice()..b"3".as_slice()).unwrap();
     let result: Vec<Item> = iter.rev().try_collect().unwrap();
 
     assert_eq!(result.len(), 1);
@@ -364,7 +364,7 @@ fn test_start_with_scenario() {
             .primary()
             .unwrap()
             .start_with(p.to_string().as_str())
-            .try_collect()
+            .unwrap().try_collect()
             .unwrap();
         assert_eq!(result.len(), 3);
 
@@ -438,7 +438,7 @@ fn test_start_with_by_key_scenario_write_txn() {
             .secondary(ItemIdFlagKey::flag)
             .unwrap()
             .start_with(p.to_string().as_str())
-            .try_collect()
+            .unwrap().try_collect()
             .unwrap();
         assert_eq!(result.len(), 3);
 
@@ -485,7 +485,7 @@ fn test_start_with_by_key_scenario_readonly_txn() {
             .secondary(ItemIdFlagKey::flag)
             .unwrap()
             .start_with(p.to_string().as_str())
-            .try_collect()
+            .unwrap().try_collect()
             .unwrap();
         assert_eq!(result.len(), 3);
 
@@ -516,7 +516,7 @@ fn test_txn_write_iter() {
     rw.commit().unwrap();
 
     let rw = db.rw_transaction().unwrap();
-    let result: Vec<Item> = rw.scan().primary().unwrap().all().try_collect().unwrap();
+    let result: Vec<Item> = rw.scan().primary().unwrap().all().unwrap().try_collect().unwrap();
     assert_eq!(result.len(), 2);
 
     let obj1 = result.get(0).unwrap();
@@ -550,7 +550,7 @@ fn test_txn_write_iter_range() {
         .primary()
         .unwrap()
         .range(..2_i32.to_be_bytes().as_slice())
-        .try_collect()
+        .unwrap().try_collect()
         .unwrap();
     assert_eq!(result.len(), 1);
 
@@ -563,7 +563,7 @@ fn test_txn_write_iter_range() {
         .primary()
         .unwrap()
         .range(2_i32.to_be_bytes().as_slice()..)
-        .try_collect()
+        .unwrap().try_collect()
         .unwrap();
     assert_eq!(result.len(), 2);
 
@@ -580,7 +580,7 @@ fn test_txn_write_iter_range() {
         .primary()
         .unwrap()
         .range(2_i32.to_be_bytes().as_slice()..3_i32.to_be_bytes().as_slice())
-        .try_collect()
+        .unwrap().try_collect()
         .unwrap();
     assert_eq!(result.len(), 1);
 
@@ -622,7 +622,7 @@ fn test_txn_write_start_with_scenario() {
             .primary()
             .unwrap()
             .start_with(p.to_string().as_str())
-            .try_collect()
+            .unwrap().try_collect()
             .unwrap();
         assert_eq!(result.len(), 3);
 
@@ -691,6 +691,7 @@ fn test_scan_range() {
         .secondary(ItemScanRangeKey::nr)
         .unwrap()
         .range(0..10)
+        .unwrap()
         .collect::<Result<Vec<ItemScanRange>, _>>()
         .unwrap()
         .iter()
@@ -703,6 +704,7 @@ fn test_scan_range() {
         .secondary(ItemScanRangeKey::nr)
         .unwrap()
         .range(2..3)
+        .unwrap()
         .collect::<Result<Vec<ItemScanRange>, _>>()
         .unwrap()
         .iter()
@@ -715,6 +717,7 @@ fn test_scan_range() {
         .secondary(ItemScanRangeKey::unique_nr)
         .unwrap()
         .range(1..3)
+        .unwrap()
         .collect::<Result<Vec<ItemScanRange>, _>>()
         .unwrap()
         .iter()
@@ -727,6 +730,7 @@ fn test_scan_range() {
         .secondary(ItemScanRangeKey::unique_nr)
         .unwrap()
         .range(1..=3)
+        .unwrap()
         .collect::<Result<Vec<ItemScanRange>, _>>()
         .unwrap()
         .iter()
@@ -739,6 +743,7 @@ fn test_scan_range() {
         .secondary(ItemScanRangeKey::unique_nr)
         .unwrap()
         .range(3..=3)
+        .unwrap()
         .collect::<Result<Vec<ItemScanRange>, _>>()
         .unwrap()
         .iter()
@@ -751,6 +756,7 @@ fn test_scan_range() {
         .secondary(ItemScanRangeKey::nr)
         .unwrap()
         .range(2..=3)
+        .unwrap()
         .collect::<Result<Vec<ItemScanRange>, _>>()
         .unwrap()
         .iter()
@@ -763,6 +769,7 @@ fn test_scan_range() {
         .secondary(ItemScanRangeKey::nr)
         .unwrap()
         .range(2..=2)
+        .unwrap()
         .collect::<Result<Vec<ItemScanRange>, _>>()
         .unwrap()
         .iter()
@@ -775,6 +782,7 @@ fn test_scan_range() {
         .secondary(ItemScanRangeKey::nr)
         .unwrap()
         .range(0..=2)
+        .unwrap()
         .collect::<Result<Vec<ItemScanRange>, _>>()
         .unwrap()
         .iter()
@@ -838,7 +846,7 @@ fn test_low_level_scan_range() {
         .secondary(ItemLowLevelScanRangeKey::secondary_key)
         .unwrap()
         .all()
-        .try_collect()
+        .unwrap().try_collect()
         .unwrap();
     assert_eq!(result.len(), 2);
     assert_eq!(result[0].secondary_key, vec![2]);
diff --git a/tests/upgrade/from_0_7_x_to_0_8_x.rs b/tests/upgrade/from_0_7_x_to_0_8_x.rs
index 5537b86..824e8a5 100644
--- a/tests/upgrade/from_0_7_x_to_0_8_x.rs
+++ b/tests/upgrade/from_0_7_x_to_0_8_x.rs
@@ -121,7 +121,7 @@ fn upgrade_from_0_7_x_to_0_8_x() {
         .secondary(Item2Key::name)
         .unwrap()
         .range("item2_5".."item2_599")
-        .try_collect()
+        .unwrap().try_collect()
         .unwrap();
     assert_eq!(items.len(), 110);
 
@@ -130,7 +130,7 @@ fn upgrade_from_0_7_x_to_0_8_x() {
         .secondary(Item2Key::name)
         .unwrap()
         .range("item2_5"..="item2_599")
-        .try_collect()
+        .unwrap().try_collect()
         .unwrap();
     assert_eq!(items.len(), 111);
 }