Bought a new Chateau Pro ax 2 weeks ago and today tried to insert a USB drive.
But no matter how I tried, the USB drive just cannot show up in the /disk print.
I inserted this drive to hAP ac2 and it immediately showed up. I format it on the hAP ac2 ( ext 4) and put it back on Chateau , still no luck.
Is there any other way to try ?
As always then posting questions here is very important to show what version of RouterOS you are on the device.
And what power drives the device POE or regular power adapter ?
That pretty weird. To @patrikg point, if you're not running that latest stable version (7.19.6 at time of writing)... that be first thing to try.
You might also want to confirm the USB device is showing up in /system/resources, since it could just not be detecting the USB device before it even get to trying mounting. Not going to fix anything, but at least give clue on underlying issue.
Thank you ! It is running on 7.19.4 with the factory AC adapter. And the USB device is not showing up in /system/resources as well.
Maybe I should consider to netinstall ?
[brg3466@Chateau] > /sys resource/usb print
Columns: DEVICE, VENDOR, NAME, SPEED
# DEVICE VENDOR NAME SPEED
0 3-0 Linux 5.6.3 xhci-hcd xHCI Host Controller 480
1 1-0 Linux 5.6.3 xhci-hcd xHCI Host Controller 480
2 4-0 Linux 5.6.3 xhci-hcd xHCI Host Controller 5000
3 2-0 Linux 5.6.3 xhci-hcd xHCI Host Controller 5000
[brg3466@Chateau] >
What brand of USB drive is this ?
Have you tried power toggle on USB bus for 5-10s and then check to see if it becomes visible then ?
Some brands take a bit more time before they are recognized.
I don't think that would help. /system/resource/usb/print only shows devices as enumerated by USB subsystem of Linux kernel. Even if attached USB devices requires some driver, which is not installed, it should appear on this list - in other words: having device listed in this list doesn't mean it'll work. But if device is not listed in this list, it definitiely won't work.
So if advice by @holvoetn doesn't work, then there's some fundamental incompatibility between Chateau's hardware and USB stick.
If you connect another USB device (not necessarily flash disk) to same Chateau's USB port, does it appear on the list of USB devices? If it doesn't, then USB port might be physically damaged (connections unsoldered/broken or something like that).
@holvoetn @mkx thank you both for the suggestion ! Mystery solved ! I inserted a couple of USB ( all USB2.0) into Chateau, just to try and none showed up. I decided to have a last try, and happen to find a USB3.0 drive. Guess what ? It showed up !!!
USB brand: Lenovo, Sandisk, etc. The final one which showed up is Sandisk 32G. But I still cannot understand why all USB2.0 cannot be recognized by Chateau.
That's odd indeed.
USB2 should always work.
If there is one brand where I would expect problems with ... it's Sandisk.
There is years-long standing bug with RB5009 where some Sandisk sticks will only be recognized as USB2 instead of USB3 right after boot. You have to play a bit with USB power timing before it gets properly recognized.
It might be worthwhile to have one of the failing disks inserted again, reboot and then create supout.rif for support so they can check what goes wrong.
I sent the supout.rif to Mikrotik. And they suggested to netinstall. 
@mkx
@brg3466 Please come back and report status after netinstall. I'm intrigued.
Sorry for the late feedback. today I have some time and did the netinstall. Unfortunately, it’s same behavior. USB3 immediately works but USB2.0 doesn’t.
I tried 4-5 different brand USB2.0, none can be recognized by Chateau pro ax.
Don’t know if it is just me or other chateau pro ax has the same issue. Appreciate if any other Chateau Pro ax owner can give some input.
I have the same router tried usb 2.0 and usb 3.0 sticks nothing gets recognized …. kingston and adata sticks … they work fine in a AX3
update…. I tested a usb hub with usb 3.0 and 2.0 ports and the ports get recognized and show up but drives don’t get recognized…. this looks like a kernel issue…. not a hardware problem….