diff --git a/components/CharacterGrid/index.tsx b/components/CharacterGrid/index.tsx
index bb0d01d9..af9b4721 100644
--- a/components/CharacterGrid/index.tsx
+++ b/components/CharacterGrid/index.tsx
@@ -66,7 +66,7 @@ const CharacterGrid = (props: Props) => {
   useEffect(() => {
     let initialPreviousUncapValues: { [key: number]: number } = {}
     Object.values(appState.grid.characters).map((o) => {
-      o ? (initialPreviousUncapValues[o.position] = o.uncap_level) : -1
+      o ? (initialPreviousUncapValues[o.position] = o.uncap_level) : 0
     })
     setPreviousUncapValues(initialPreviousUncapValues)
   }, [appState.grid.characters])
diff --git a/components/SummonGrid/index.tsx b/components/SummonGrid/index.tsx
index 8303801c..e115da5d 100644
--- a/components/SummonGrid/index.tsx
+++ b/components/SummonGrid/index.tsx
@@ -71,8 +71,8 @@ const SummonGrid = (props: Props) => {
       initialPreviousUncapValues[6] =
         appState.grid.summons.friendSummon.uncap_level
 
-    Object.values(appState.grid.summons.allSummons).map(
-      (o) => (initialPreviousUncapValues[o.position] = o.uncap_level)
+    Object.values(appState.grid.summons.allSummons).map((o) =>
+      o ? (initialPreviousUncapValues[o.position] = o.uncap_level) : 0
     )
 
     setPreviousUncapValues(initialPreviousUncapValues)
@@ -190,7 +190,13 @@ const SummonGrid = (props: Props) => {
       appState.grid.summons.mainSummon.uncap_level = uncapLevel
     else if (appState.grid.summons.friendSummon && position == 6)
       appState.grid.summons.friendSummon.uncap_level = uncapLevel
-    else appState.grid.summons.allSummons[position].uncap_level = uncapLevel
+    else {
+      const summon = appState.grid.summons.allSummons[position]
+      if (summon) {
+        summon.uncap_level = uncapLevel
+        appState.grid.summons.allSummons[position] = summon
+      }
+    }
   }
 
   function storePreviousUncapValue(position: number) {
@@ -202,9 +208,10 @@ const SummonGrid = (props: Props) => {
     else if (appState.grid.summons.friendSummon && position == 6)
       newPreviousValues[position] =
         appState.grid.summons.friendSummon.uncap_level
-    else
-      newPreviousValues[position] =
-        appState.grid.summons.allSummons[position].uncap_level
+    else {
+      const summon = appState.grid.summons.allSummons[position]
+      newPreviousValues[position] = summon ? summon.uncap_level : 0
+    }
 
     setPreviousUncapValues(newPreviousValues)
   }
diff --git a/components/WeaponGrid/index.tsx b/components/WeaponGrid/index.tsx
index e4be7183..86169c2c 100644
--- a/components/WeaponGrid/index.tsx
+++ b/components/WeaponGrid/index.tsx
@@ -63,8 +63,8 @@ const WeaponGrid = (props: Props) => {
       initialPreviousUncapValues[-1] =
         appState.grid.weapons.mainWeapon.uncap_level
 
-    Object.values(appState.grid.weapons.allWeapons).map(
-      (o) => (initialPreviousUncapValues[o.position] = o.uncap_level)
+    Object.values(appState.grid.weapons.allWeapons).map((o) =>
+      o ? (initialPreviousUncapValues[o.position] = o.uncap_level) : 0
     )
 
     setPreviousUncapValues(initialPreviousUncapValues)
@@ -178,16 +178,30 @@ const WeaponGrid = (props: Props) => {
   const updateUncapLevel = (position: number, uncapLevel: number) => {
     if (appState.grid.weapons.mainWeapon && position == -1)
       appState.grid.weapons.mainWeapon.uncap_level = uncapLevel
-    else appState.grid.weapons.allWeapons[position].uncap_level = uncapLevel
+    else {
+      const weapon = appState.grid.weapons.allWeapons[position]
+      if (weapon) {
+        weapon.uncap_level = uncapLevel
+        appState.grid.weapons.allWeapons[position] = weapon
+      }
+    }
   }
 
   function storePreviousUncapValue(position: number) {
     // Save the current value in case of an unexpected result
     let newPreviousValues = { ...previousUncapValues }
-    newPreviousValues[position] =
-      appState.grid.weapons.mainWeapon && position == -1
-        ? appState.grid.weapons.mainWeapon.uncap_level
-        : appState.grid.weapons.allWeapons[position].uncap_level
+
+    if (appState.grid.weapons.mainWeapon && position == -1) {
+      newPreviousValues[position] = appState.grid.weapons.mainWeapon.uncap_level
+    } else {
+      const weapon = appState.grid.weapons.allWeapons[position]
+      if (weapon) {
+        newPreviousValues[position] = weapon.uncap_level
+      } else {
+        newPreviousValues[position] = 0
+      }
+    }
+
     setPreviousUncapValues(newPreviousValues)
   }