Usermanager being reset on every reboot

RouterOS The User Manager
1

Hi, my RB750r2 always lost usermanager’s configuration and any user records on every reboot… is anyone have that problem too and have fix it?
I already update the packages to the latest version (6.46.4) and have upgrade the firmware

                  version: 6.46.4 (stable)
               build-time: Feb/21/2020 11:26:37
         factory-software: 6.28
              free-memory: 33.0MiB
             total-memory: 64.0MiB
                      cpu: MIPS 24Kc V7.4
                cpu-count: 1
            cpu-frequency: 850MHz
                 cpu-load: 8%
           free-hdd-space: 1464.0KiB
          total-hdd-space: 16.0MiB
  write-sect-since-reboot: 267
         write-sect-total: 214362
               bad-blocks: 0%
        architecture-name: mipsbe
               board-name: hEX lite
                 platform: MikroTik




       routerboard: yes
        board-name: hEX lite
             model: RouterBOARD 750 r2
     serial-number: 67D207041CF1
     firmware-type: qca9531L
  factory-firmware: 3.36
  current-firmware: 6.46.4
  upgrade-firmware: 6.46.4
2

Hi this is my 1St reply here
so do you notice this issue before the upgrading or after
if it is started after the upgrade try to:
1.rebuild UM data base if not working.
2. downgrade your version to the old one and check it it is work
3. if both not working try to re setup the user-manager
i am beginner in microtik so maybe the other members have better answer to your issue