diff --git a/src/Contact/Avatar.php b/src/Contact/Avatar.php
index f43ed7b8c..1dd2f9cee 100644
--- a/src/Contact/Avatar.php
+++ b/src/Contact/Avatar.php
@@ -263,7 +263,7 @@ class Avatar
 	{
 		$localFile = self::getCacheFile($avatar);
 		if (!empty($localFile)) {
-			unlink($localFile);
+			@unlink($localFile);
 			Logger::debug('Unlink avatar', ['avatar' => $avatar]);
 		}
 	}
diff --git a/src/Core/Installer.php b/src/Core/Installer.php
index ff759c9fe..9a9bdfb5f 100644
--- a/src/Core/Installer.php
+++ b/src/Core/Installer.php
@@ -486,6 +486,13 @@ class Installer
 		);
 		$returnVal = $returnVal ? $status : false;
 
+		$status = $this->checkFunction('gmp_strval',
+			DI::l10n()->t('GNU Multiple Precision PHP module'),
+			DI::l10n()->t('Error: GNU Multiple Precision PHP module required but not installed.'),
+			true
+		);
+		$returnVal = $returnVal ? $status : false;
+
 		return $returnVal;
 	}