Cisco 3850 stacking issue

[Herman2018]

Spoiler

Hi, we are trying to stack 2x cisco 3850-48p with one Cisco 3850-24p, the OS version is same, after stacking, run the command "show sw", the result looks good, but the LED " stack" on the front panel is not on. Then we tried to configure the switch, however, if reboot the stack (3 switches ) or power cycle all 3 switches, then the configuration is gone, reverted to default config. Can someone pls help advise the root cause of this issue? thanks in advance! 

[marce1000 · Accepted solution]

                  >... then the configuration is gone,
   1) Make sure to save the configuration after changes (# write mem)
   2) If the problem is persistent , check the value of the configuration register(first)  and or use 
       these settings (on the stack master)  :
                        # config-register 0x102
                        # no system ignore startupconfig switch all

 M.

[Herman2018]

thank you so much @marce1000 

[Edson A. Hernandez]

• Ensure that the stacking cables and modules are securely connected
• Confirm that all switches have the same license level.
• Check the stack priority configuration. Ensure that the switch you want to use as the stack master has the highest priority set. You can check this with the command show switch [switch-number].
• If the above steps are correct and the issue persists, there might be a software issue. Consider upgrading the switches to the latest recommended software version or contacting Cisco support for further assistance.

[Herman2018]

thanks @Edson A. Hernandez  for your advice !