Do the regular routine of unplugging the power-cord and holding the mode button and then plugging back until you land in recover mode (switch:)

Now enter the following commands

switch: SWITCH_IGNORE_STARTUP_CFG=1

switch: SWITCH_DISABLE_PASSWORD_RECOVERY=0

switch: boot

After reboot

Switch(config)#no system ignore startupconfig switch all

Switch(config)#system disable password recovery switch all

Switch#copy running startup