diff --git a/code/Report.php b/code/Report.php
index b934b579..6120a4c3 100644
--- a/code/Report.php
+++ b/code/Report.php
@@ -218,7 +218,7 @@ class Report extends ViewableData
      */
     protected function sanitiseClassName($class)
     {
-        return str_replace('\\', '-', $class);
+        return str_replace('\\', '-', $class ?? '');
     }
 
 
@@ -286,12 +286,12 @@ class Report extends ViewableData
         $reports = ClassInfo::subclassesFor(get_called_class());
 
         $reportsArray = [];
-        if ($reports && count($reports) > 0) {
+        if ($reports && count($reports ?? []) > 0) {
             $excludedReports = static::get_excluded_reports();
             // Collect reports into array with an attribute for 'sort'
             foreach ($reports as $report) {
                 // Don't use the Report superclass, or any excluded report classes
-                if (in_array($report, $excludedReports)) {
+                if (in_array($report, $excludedReports ?? [])) {
                     continue;
                 }
                 $reflectionClass = new ReflectionClass($report);
@@ -484,7 +484,7 @@ class Report extends ViewableData
         $results = $this->extend($methodName, $member);
         if ($results && is_array($results)) {
             // Remove NULLs
-            $results = array_filter($results, function ($v) {
+            $results = array_filter($results ?? [], function ($v) {
                 return !is_null($v);
             });
             // If there are any non-NULL responses, then return the lowest one of them.
diff --git a/code/ReportAdmin.php b/code/ReportAdmin.php
index 19a1fc24..83aa57cb 100644
--- a/code/ReportAdmin.php
+++ b/code/ReportAdmin.php
@@ -139,7 +139,7 @@ class ReportAdmin extends LeftAndMain implements PermissionProvider
      */
     protected function unsanitiseClassName($class)
     {
-        return str_replace('-', '\\', $class);
+        return str_replace('-', '\\', $class ?? '');
     }
 
     /**
@@ -155,7 +155,7 @@ class ReportAdmin extends LeftAndMain implements PermissionProvider
      */
     public static function has_reports()
     {
-        return sizeof(Report::get_reports()) > 0;
+        return sizeof(Report::get_reports() ?? []) > 0;
     }
 
     /**
diff --git a/code/SideReportView.php b/code/SideReportView.php
index 171ef960..d80058b9 100644
--- a/code/SideReportView.php
+++ b/code/SideReportView.php
@@ -79,9 +79,9 @@ class SideReportView extends ViewableData
 
         // Formatting, a la TableListField
         if (!empty($info['formatting'])) {
-            $format = str_replace('$value', "__VAL__", $info['formatting']);
-            $format = preg_replace('/\$([A-Za-z0-9-_]+)/', '$record->$1', $format);
-            $format = str_replace('__VAL__', '$val', $format);
+            $format = str_replace('$value', "__VAL__", $info['formatting'] ?? '');
+            $format = preg_replace('/\$([A-Za-z0-9-_]+)/', '$record->$1', $format ?? '');
+            $format = str_replace('__VAL__', '$val', $format ?? '');
             $val = eval('return "' . $format . '";');
         }
 
@@ -90,7 +90,7 @@ class SideReportView extends ViewableData
 
         $classClause = "";
         if (isset($info['title'])) {
-            $cssClass = preg_replace('/[^A-Za-z0-9]+/', '', $info['title']);
+            $cssClass = preg_replace('/[^A-Za-z0-9]+/', '', $info['title'] ?? '');
             $classClause = "class=\"$cssClass\"";
         }