Hi

Do you have any idea why my MT is loosing graph data after reboot?

ros code

[admin@MikroTik] /tool graphing> print
   store-every: 5min
  page-refresh: 300
[admin@MikroTik] /tool graphing> 
[admin@MikroTik] /tool graphing interface> print
Flags: X - disabled 
 #   INTERFACE     ALLOW-ADDRESS                                  STORE-ON-DISK
 0   all           192.168.88.0/24                                yes

[admin@MikroTik] /system routerboard> print 
       routerboard: yes
             model: 2011UiAS-2HnD
     serial-number: 444A04E9417D
  current-firmware: 3.18
  upgrade-firmware: 3.18

It happened on previous software releases <6.18.
Is there anything else to be configured?

I need az USB stick to store graphs on it?
What i need to configure?

What version do you have? Update to latest. Aren't you rebooting before the graphs are saved? Check the save interval...
Saving to other than local flash is not supported.

I need az USB stick to store graphs on it?
What i need to configure?

This is old post - active again - Probably you don't need usb stick-not supported graphs don't use lot of space
if you are losing your graphs after reboot simply It may be related to your RB clock, just setup NTP client and put correct time zone
If NTP client is not adjust, after reboot your RB clock will be reset to default so this will affect your graphs.
Just giving my 2 cent.