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javisensacion
New Member
January 28, 2026
Question

FortiOS Upgrade from 7.6.4 to 7.6.5 no coming back after upgrade

  • January 28, 2026
  • 4 replies
  • 866 views

I have these issues on some FG80F models, where, after I upgrade from 7.6.4 to 7.6.5, the firewalls won't come back online, and the upgrade was executed remotely

 

Anyone with the same or a similar issue after upgrading to 7.6.5

4 replies

AEK
SuperUser
SuperUser
January 28, 2026

Remotely you mean IPsec?

If so then probably the the firewall is up but the tunnel is down?

AEK
BillH_FTNT
Staff
Staff
January 29, 2026

Hi @javisensacion 

1. Can you ping the management IP?
2. Can you SSH to the management IP?
3. Do you have any traffic to verify that the traffic is normal?

Regards

Bill

javisensacion
New Member
February 2, 2026

One of the clusters went into split-brain mode after the upgrade, and I detected part of the config deletion in the second one. Also, I had another one that took between 10 and 15 min after the upgrade to come up...

 

So far never had this issue when I went from 7.48 to 7.60 , then 7.6.3, is from 7.6.4 to 7.6.5

 

BillH_FTNT
Staff
Staff
February 3, 2026

Hi @javisensacion 

Do you have a ticket for this issue ? I would like to test it in my lab. I may use the cfg in ticket. Thank you

Bill

javisensacion
New Member
February 2, 2026

also I have the cluster configured in A-P mode 

ede_pfau
SuperUser
SuperUser
February 3, 2026

@javisensacion wrote:

I have these issues on some FG80F models, where, after I upgrade from 7.6.4 to 7.6.5, the firewalls won't come back online, and the upgrade was executed remotely

 

Anyone with the samei or a similar issue after upgrading to 7.6.5


I once encountered the same situation when upgrading, and was able to 'fix' it, in a way.

Issue was that the secondary upgraded, and then the primary was not demoted to secondary. That meant 'split brain' on 2 different OS versions.

The fix I found after a while (and a lot of sweat as this was remote) was to reboot the upgraded, originally secondary, unit. This way, no split brain, primary completed the upgrade, cluster came back up. When the update took a bit longer I had to reboot the secondary repeatedly to keep it out of the cluster.