diff --git a/core/Command/Maintenance/UpdateHtaccess.php b/core/Command/Maintenance/UpdateHtaccess.php
index 67c6db22b21ca..9243567afb4b7 100644
--- a/core/Command/Maintenance/UpdateHtaccess.php
+++ b/core/Command/Maintenance/UpdateHtaccess.php
@@ -39,7 +39,7 @@ protected function execute(InputInterface $input, OutputInterface $output): int
 			$output->writeln('.htaccess has been updated');
 			return 0;
 		} else {
-			$output->writeln('<error>Error updating .htaccess file, not enough permissions or "overwrite.cli.url" set to an invalid URL?</error>');
+			$output->writeln('<error>Error updating .htaccess file, not enough permissions, not enough free space or "overwrite.cli.url" set to an invalid URL?</error>');
 			return 1;
 		}
 	}
diff --git a/lib/private/Setup.php b/lib/private/Setup.php
index 749d4c7bdb093..75b581db7c4f3 100644
--- a/lib/private/Setup.php
+++ b/lib/private/Setup.php
@@ -560,6 +560,14 @@ public static function updateHtaccess() {
 		}
 
 		if ($content !== '') {
+			// Never write file back if disk space should be too low
+			if (function_exists('disk_free_space')) {
+				$df = disk_free_space(\OC::$SERVERROOT);
+				$size = strlen($content) + 10240;
+				if ($df !== false && $df < (float)$size) {
+					throw new \Exception(\OC::$SERVERROOT . " does not have enough space for writing the htaccess file! Not writing it back!");
+				}
+			}
 			//suppress errors in case we don't have permissions for it
 			return (bool)@file_put_contents($setupHelper->pathToHtaccess(), $htaccessContent . $content . "\n");
 		}