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shijug
Visitor III
May 2, 2026
Question

URGENT: FortiGate 401E Daily System Hang – Console Unresponsive

  • May 2, 2026
  • 4 replies
  • 110 views

We are experiencing a critical and recurring issue with our FortiGate 401E.

  • The device hangs once or twice daily
  • Issue has been ongoing for ~2 years
  • During the hang:
    • No traffic passes through the firewall
    • GUI and SSH become inaccessible
    • Console is completely unresponsive
  • Only manual reboot restores operation

This is impacting production services significantly.

🔧 Troubleshooting Done:

  • Firmware upgraded from v7.4.0 to v7.4.8
  • Issue persists even after upgrade
  • No configuration changes correlate with the issue
  • Problem occurs randomly without a clear pattern

    4 replies

    Toshi_Esumi
    SuperUser
    Toshi_Esumi
    SuperUser
    May 2, 2026

    Sounds like a hardware related issue to me. I would open a ticket at TAC to get it examined. Then if determined, they would proceed with RMA.
    I wouldn’t wait for like 2 years. That’s crazy.

    Toshi

      AEK
      SuperUser
      AEK
      SuperUser
      May 3, 2026

      Additionally to Toshi’s suggestion, the described symptoms may also be caused by possible extreme conserve mode. You can check the system logs after FGT reboot and see if it was caused by conserve mode, or you can also find other relevant messages.

      Following command can also show if there was a crash.

      diag debug crashlog read

      But it can be difficult to understand the content.

      AEK
        S
        shijugAuthor
        Visitor III
        May 11, 2026

        yes,,I tried 

        Killed daemon sflowd 0*0

        BillH_FTNT
        Staff
        BillH_FTNT
        Staff
        May 11, 2026

        Hi ​@shijug Could you pls share the content of crashlog ? or something related to sflowd ? Thank you

        Bill

        BillH_FTNT
        Staff
        BillH_FTNT
        Staff
        May 3, 2026

        Hi ​@shijug 

        We need additional logs to identify the root cause.

        1. Please connect a console cable and continuously monitor the kernel logs through the console. The console should be connected in advance to capture the complete logs; connecting it after the issue occurs may result in the device becoming unresponsive and logs being missed.
        1. Please also share system, event, and traffic logs collected before the issue occurs. This will help identify what factors changed prior to the problem.
        1. As AEK mentioned, please run dia debug crashlog read to check whether the device is in conserve mode and to review memory status.
        1. I will share a monitoring script with you later.

        My name is Bill from fortinet; my email is bhoang@fortinet.com

        Thanks

        Bill

          S
          shijugAuthor
          Visitor III
          May 17, 2026

          Didnt receive any script

          BillH_FTNT
          Staff
          BillH_FTNT
          Staff
          May 17, 2026

          Hi Shijug

          The tool has been blocked by our company’s email security. I am looking for another way to share it with you. If you have a ticket, that would be helpful—I can share it through the FortiCare ticket. Thank you.

          In the meantime, could you please share the logs as requested in my previous message? Thanks.

           

          Bill

          AEK
          SuperUser
          AEK
          SuperUser
          May 3, 2026

          On the other hand I recommend to update to 7.4.11 which is more stable than 7.4.8.

          I mean you have some chance to fix it just with this update.

          AEK
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