diff --git a/core/command/db/converttype.php b/core/command/db/converttype.php
index 809374950d3..39e87853d60 100644
--- a/core/command/db/converttype.php
+++ b/core/command/db/converttype.php
@@ -99,6 +99,11 @@ class ConvertType extends Command {
 				'Converting to SQLite (sqlite3) is currently not supported.'
 			);
 		}
+		if ($type === 'mssql') {
+			throw new \InvalidArgumentException(
+				'Converting to Microsoft SQL Server (mssql) is currently not supported.'
+			);
+		}
 		if ($type === $this->config->getValue('dbtype', '')) {
 			throw new \InvalidArgumentException(sprintf(
 				'Can not convert from %1$s to %1$s.',