diff --git a/lib/private/Installer.php b/lib/private/Installer.php
index 0ae374ce6e2ce..343306f3e1742 100644
--- a/lib/private/Installer.php
+++ b/lib/private/Installer.php
@@ -241,6 +241,10 @@ public function downloadApp(string $appId, bool $allowUnstable = false): void {
 
 				// Download the release
 				$tempFile = $this->tempManager->getTemporaryFile('.tar.gz');
+				if ($tempFile === false) {
+					throw new \RuntimeException('Could not create temporary file for downloading app archive.');
+				}
+				
 				$timeout = $this->isCLI ? 0 : 120;
 				$client = $this->clientService->newClient();
 				$client->get($app['releases'][0]['download'], ['sink' => $tempFile, 'timeout' => $timeout]);