C3850#conf t
Enter configuration commands, one per line. End with CNTL/Z.
C3850(config)#system ignore startupconfig switch all
Applying config on Switch 1...[DONE]
Applying config on Switch 2...[DONE]
C3850(config)#no system ignore startupconfig switch all
Applying config on Switch 1...[DONE]
Applying config on Switch 2...[DONE]