diff -u b/core/lib/Drupal/Core/EventSubscriber/ConfigImportSubscriber.php b/core/lib/Drupal/Core/EventSubscriber/ConfigImportSubscriber.php
--- b/core/lib/Drupal/Core/EventSubscriber/ConfigImportSubscriber.php
+++ b/core/lib/Drupal/Core/EventSubscriber/ConfigImportSubscriber.php
@@ -144,29 +144,34 @@
       }
     }
 
-    if (in_array($main_profile->getName(), $uninstalls, TRUE)) {
-      // Ensure that the active profile is not being uninstalled.
-      $profile_name = $main_profile->info['name'];
-      $config_importer->logError($this->t('Unable to uninstall the %profile profile since it is the main install profile.', ['%profile' => $profile_name]));
-    }
+    // Don't allow profiles to be uninstalled. It's possible for no profile to
+    // be set yet if the config is being imported during initial site install.
+    if (isset($main_profile)) {
+      if (in_array($main_profile->getName(), $uninstalls, TRUE)) {
+        // Ensure that the active profile is not being uninstalled.
+        $profile_name = $main_profile->info['name'];
+        $config_importer->logError($this->t('Unable to uninstall the %profile profile since it is the main install profile.', ['%profile' => $profile_name]));
+      }
 
-    $profile_names = [];
-    if ($profile_uninstalls = array_intersect_key($profiles, array_flip($uninstalls))) {
-      // Ensure that none of the parent profiles are being uninstalled.
-      foreach ($profile_uninstalls as $profile) {
-        if ($profile->getName() !== $main_profile->getName()) {
-          $profile_names[] = $module_data[$profile->getName()]->info['name'];
+      if ($profile_uninstalls = array_intersect_key($profiles, array_flip($uninstalls))) {
+        // Ensure that none of the parent profiles are being uninstalled.
+        $profile_names = [];
+        foreach ($profile_uninstalls as $profile) {
+          if ($profile->getName() !== $main_profile->getName()) {
+            $profile_names[] = $module_data[$profile->getName()]->info['name'];
+          }
+        }
+        if (!empty($profile_names)) {
+          $message = $this->formatPlural(count($profile_names),
+            'Unable to uninstall the :profile profile since it is a parent of another installed profile.',
+            'Unable to uninstall the :profile profiles since they are parents of another installed profile.',
+            [':profile' => implode(', ', $profile_names)]
+          );
+          $config_importer->logError($message);
         }
-      }
-      if (!empty($profile_names)) {
-        $message = $this->formatPlural(count($profile_names),
-          'Unable to uninstall the :profile profile since it is a parent of another installed profile.',
-          'Unable to uninstall the :profile profiles since they are parents of another installed profile.',
-          [':profile' => implode(', ', $profile_names)]
-        );
-        $config_importer->logError($message);
       }
     }
+
   }
 
   /**