diff --git a/src/Fields/KeyValueField.php b/src/Fields/KeyValueField.php
index d8a59e6..893037b 100755
--- a/src/Fields/KeyValueField.php
+++ b/src/Fields/KeyValueField.php
@@ -148,7 +148,7 @@ protected function createSelectList($number, $name, $values, $selected = '', $pl
             $options .= HTML::createTag('option', $attrs, Convert::raw2xml($title));
         }
 
-        if (count($values)) {
+        if (count($values ?? [])) {
             $attrs = [
                 'class' => 'text mventryfield mvdropdown '.($this->extraClass() ? $this->extraClass() : ''),
                 'id' => $this->id().MultiValueTextField::KEY_SEP.$number,
@@ -189,7 +189,7 @@ public function setValue($v, $data = null)
                 $newVal = [];
 
                 for ($i = 0, $c = count($v['key']); $i < $c; $i++) {
-                    if (strlen($v['key'][$i]) && strlen($v['val'][$i])) {
+                    if (strlen($v['key'][$i] ?? '') && strlen($v['val'][$i] ?? '')) {
                         $newVal[$v['key'][$i]] = $v['val'][$i];
                     }
                 }
diff --git a/src/Fields/MultiValueCheckboxField.php b/src/Fields/MultiValueCheckboxField.php
index f28e32f..ebe56fd 100755
--- a/src/Fields/MultiValueCheckboxField.php
+++ b/src/Fields/MultiValueCheckboxField.php
@@ -49,7 +49,7 @@ public function Field($properties = [])
 
             if ($this->storeKeys && is_array($values)) {
                 // use the keys instead, as that's how we've stored things
-                $values = array_keys($values);
+                $values = array_keys($values ?? []);
             }
         }
 
@@ -77,8 +77,8 @@ public function Field($properties = [])
                         }
                     }
                 } elseif ($values && is_string($values)) {
-                    $items = explode(',', $values);
-                    $items = str_replace('{comma}', ',', $items);
+                    $items = explode(',', $values ?? '');
+                    $items = str_replace('{comma}', ',', $items ?? '');
                 }
             }
         } else {
@@ -86,8 +86,8 @@ public function Field($properties = [])
             if (is_a($values, 'DataObjectSet') || is_array($values)) {
                 $items = $values;
             } else {
-                $items = explode(',', $values);
-                $items = str_replace('{comma}', ',', $items);
+                $items = explode(',', $values ?? '');
+                $items = str_replace('{comma}', ',', $items ?? '');
             }
         }
 
@@ -117,15 +117,15 @@ public function Field($properties = [])
 
                     $odd        = ($odd + 1) % 2;
                     $extraClass = $odd ? 'odd' : 'even';
-                    $extraClass .= ' val'.str_replace(' ', '', $key);
-                    $itemID     = $this->id().'_'.preg_replace('/[^a-zA-Z0-9]+/', '', $key);
+                    $extraClass .= ' val'.str_replace(' ', '', $key ?? '');
+                    $itemID     = $this->id().'_'.preg_replace('/[^a-zA-Z0-9]+/', '', $key ?? '');
                     $checked    = '';
                 if (isset($items)) {
-                    $checked = (in_array($key, $items) || in_array($key, $this->defaultItems))
+                    $checked = (in_array($key, $items ?? []) || in_array($key, $this->defaultItems ?? []))
                         ? ' checked="checked"' : '';
                 }
 
-                    $disabled = ($this->disabled || in_array($key, $this->disabledItems))
+                    $disabled = ($this->disabled || in_array($key, $this->disabledItems ?? []))
                         ? $disabled = ' disabled="disabled"'
                 : '';
                     $options .= "<li class=\"$extraClass\"><input id=\"$itemID\" name=\"$this->name[$key]\""
@@ -220,7 +220,7 @@ public function dataValue()
             $filtered = [];
             foreach ($this->value as $item) {
                 if ($item) {
-                    $filtered[] = str_replace(",", "{comma}", $item);
+                    $filtered[] = str_replace(",", "{comma}", $item ?? '');
                 }
             }
 
@@ -271,7 +271,7 @@ public function performReadonlyTransformation()
                 // Items is an array or single piece of string (including comma seperated string)
             } else {
                 if (!is_array($items)) {
-                    $items = preg_split('/ *, */', trim($items));
+                    $items = preg_split('/ *, */', trim($items ?? ''));
                 }
 
                 foreach ($items as $item) {
diff --git a/src/Fields/MultiValueListField.php b/src/Fields/MultiValueListField.php
index 24690b7..838b9e2 100755
--- a/src/Fields/MultiValueListField.php
+++ b/src/Fields/MultiValueListField.php
@@ -42,7 +42,7 @@ public function Field($properties = [])
 
         foreach ($this->source as $index => $title) {
             $attrs = ['value' => $index];
-            if (in_array($index, $this->value)) {
+            if (in_array($index, $this->value ?? [])) {
                 $attrs['selected'] = 'selected';
             }
             $options .= HTML::createTag('option', $attrs, Convert::raw2xml($title));
diff --git a/src/Fields/MultiValueTextField.php b/src/Fields/MultiValueTextField.php
index 6db95ba..02fdad3 100755
--- a/src/Fields/MultiValueTextField.php
+++ b/src/Fields/MultiValueTextField.php
@@ -62,11 +62,11 @@ public function Field($properties = [])
         // add an empty row
         if (!$this->readonly) {
             // assume next pos equals to the number of existing fields which gives index+1 in a zero-indexed list
-            $attributes['id'] = $this->id().MultiValueTextField::KEY_SEP.count($fields);
+            $attributes['id'] = $this->id().MultiValueTextField::KEY_SEP.count($fields ?? []);
             $fields[] = $this->createInput($attributes);
         }
 
-        if (count($fields)) {
+        if (count($fields ?? [])) {
             return '<ul id="'.$this->id().'" class="multivaluefieldlist '.$this->extraClass().'"><li>'.implode(
                 '</li><li>',
                 $fields
@@ -99,7 +99,7 @@ public function setValue($v, $data = null)
         if (is_array($v)) {
             // we've been set directly via the post - lets prune any empty values
             foreach ($v as $key => $val) {
-                if (!strlen($val)) {
+                if (!strlen($val ?? '')) {
                     unset($v[$key]);
                 }
             }
diff --git a/src/ORM/FieldType/MultiValueField.php b/src/ORM/FieldType/MultiValueField.php
index 00e7a3e..e8515e2 100755
--- a/src/ORM/FieldType/MultiValueField.php
+++ b/src/ORM/FieldType/MultiValueField.php
@@ -99,12 +99,12 @@ protected function unserializeData($data)
     {
         $value = null;
         // if we're not deserialised yet, do so
-        if (is_string($data) && strlen($data) > 1) {
+        if (is_string($data) && strlen($data ?? '') > 1) {
             // are we json encoded?
             if ($data[1] === ':') {
-                $value = \unserialize($data);
+                $value = \unserialize($data ?? '');
             } else {
-                $value = \json_decode($data, true);
+                $value = \json_decode($data ?? '', true);
             }
         }
         return $value;
@@ -155,7 +155,7 @@ public function csv()
      */
     public function Implode($separator = ', ')
     {
-        return implode($separator, $this->getValue());
+        return implode($separator ?? '', $this->getValue());
     }
 
     public function __toString()
@@ -170,7 +170,7 @@ public function __toString()
     public function ItemByKey()
     {
         $values = $this->getValue();
-        if (array_keys($values) == range(0, count($values) - 1)) {
+        if (array_keys($values ?? []) == range(0, count($values ?? []) - 1)) {
             $values = [];
         }
         return new ArrayData($values);