diff --git a/Makefile.work b/Makefile.work
index 8703a13d0..294a6c9c5 100644
--- a/Makefile.work
+++ b/Makefile.work
@@ -45,6 +45,7 @@ SHELL = /bin/bash
 
 USER := $(shell id -un)
 PWD := $(shell pwd)
+USER_LC := $(shell echo $(USER) | tr A-Z a-z)
 
 comma := ,
 
@@ -100,7 +101,7 @@ SLAVE_BASE_IMAGE = $(SLAVE_DIR)
 else
 SLAVE_BASE_IMAGE = $(SLAVE_DIR)-$(CONFIGURED_ARCH)
 endif
-SLAVE_IMAGE = $(SLAVE_BASE_IMAGE)-$(USER)
+SLAVE_IMAGE = $(SLAVE_BASE_IMAGE)-$(USER_LC)
 
 # Generate the version control build info
 $(shell SONIC_VERSION_CONTROL_COMPONENTS=$(SONIC_VERSION_CONTROL_COMPONENTS) \