diff --git a/base/setup/lib/utils/partlist.c b/base/setup/lib/utils/partlist.c
index 6bb16fed9d4..f89bbe3b645 100644
--- a/base/setup/lib/utils/partlist.c
+++ b/base/setup/lib/utils/partlist.c
@@ -3346,6 +3346,11 @@ FindSupportedSystemPartition(
      * should be our system partition.
      */
     DiskEntry = GetSystemDisk(List);
+    if (!DiskEntry)
+    {
+        /* No system disk found, directly go check the alternative disk */
+        goto UseAlternativeDisk;
+    }
 
     if (DiskEntry->DiskStyle == PARTITION_STYLE_GPT)
     {