diff --git a/BSD.md b/BSD.md
index 758e9a3..7aef49f 100644
--- a/BSD.md
+++ b/BSD.md
@@ -53,6 +53,8 @@ sudo shutdown --reboot now
 
 ## FreeDOS
 
+When installing to VirtualBox, set harddisk .vdi growable max size to 4000 MB / 4 GB, because LiveCD + BonusCD could take nearly 2 GB total disk space.
+
 update.bat
 ```
 fdnpkg update