7 Ports USB Hub acquired strange behavior after plugging in another

"You can connect 127 devices per controller. Most modern computers have multiple controllers. You're not even close to that limit.

Your problem is almost certainly power. I don't trust hard drives that don't have their own independent power. Too many variables to rely on bus power, especially if the ports aren't USB 3. Before USB 3 a powered hub could only provide 5v@500ma. Not enough for hard drives.

After USB 3 you have negotiated power delivery, enough for hard drives, but no port or hub or controller or cable must provide as much power as a hard drive requires and requests. It's negotiated, not demanded. Too many variables. Use independent power for hard drives."
Is there a limit on the amount of USB connections a computer will allow? I use a hub (external power source) w/ 10 ports. To 2 of those ports I attach other hubs. The computer doesn't recognize some hard drives on the ports. What should I do? - Quora


Sounds reasonable...

lack of power

u need multiple spliter + extra adapter that can supply more power...

Instead of using a USB hub to power that many hard drives, I would look at a hard drive enclosure which is designed to power all the of the hard drives adequately. I'm using an old AMD FX desktop computer in a case that mounts 8 3.5" hard drives. Granted it is NAS, not USB, though.

NTN said:

Your problem is almost certainly power. I don't trust hard drives that don't have their own independent power. Too many variables to rely on bus power, especially if the ports aren't USB 3. Before USB 3 a powered hub could only provide 5v@500ma. Not enough for hard drives.

After USB 3 you have negotiated power delivery, enough for hard drives, but no port or hub or controller or cable must provide as much power as a hard drive requires and requests. It's negotiated, not demanded. Too many variables. Use independent power for hard drives."

It´s not exactly a matter of trust. USB ports of any type supply 5V to the disk. A 3.5 in HDD needs 12V power, which can´t be supplied by any USB port, so it needs an external 12V power supply.

NavyLCDR said:

Instead of using a USB hub to power that many hard drives, I would look at a hard drive enclosure which is designed to power all the of the hard drives adequately. I'm using an old AMD FX desktop computer in a case that mounts 8 3.5" hard drives. Granted it is NAS, not USB, though.

yes of course
i will say same thingbut op said about usb. i think he must know the problem

I am getting the feeling I was not clear again , I have managed to sort the power issue , the whole OP was about me recognizing the power issue and solving it , I have a rare 5V and 5A adapter , this is enough to power the 7 external HDDs and it is working .

The question in hand is that it reverted from recognizing them as different Disks (Expected behavior) to just different volumes to 1 Disk , so now if I want to safely remove one of them , all will remove along and this is what I am trying to solve .

On a side notice about power I have a good understanding of the power formula , all the 7 drives work fine in current state and power factor . If I plug in a 5V 2A power adapter which is the widely available one on market it can only power 3 drives at most where the 4th may either show troubles being recognized or freeze all other 4 , however the 5V 5A power adapter helps them all be recognized and operational .

And yet again the problem I am facing is that suddenly windows recognition shifted from recognizing them as dependent hard drives to be all volumes of a single one .

Any clues why ?

Have you tried shutting down and disconnecting all the external drives,then reconnecting one at a time and checking bios recognition for each and likewise in Device manager?

nIGHTmAYOR said:

I am getting the feeling I was not clear again , I have managed to sort the power issue , the whole OP was about me recognizing the power issue and solving it , I have a rare 5V and 5A adapter , this is enough to power the 7 external HDDs and it is working .

The question in hand is that it reverted from recognizing them as different Disks (Expected behavior) to just different volumes to 1 Disk , so now if I want to safely remove one of them , all will remove along and this is what I am trying to solve .

On a side notice about power I have a good understanding of the power formula , all the 7 drives work fine in current state and power factor . If I plug in a 5V 2A power adapter which is the widely available one on market it can only power 3 drives at most where the 4th may either show troubles being recognized or freeze all other 4 , however the 5V 5A power adapter helps them all be recognized and operational .

And yet again the problem I am facing is that suddenly windows recognition shifted from recognizing them as dependent hard drives to be all volumes of a single one .

Any clues why ?

try uninstall all usb drivers ... and delete the driver (if the option available)

let w10 use their driver
and dont update using driver booster utilities or similar app to update driver.


i had same problem before... randomly disconnected my mouse and reconnect. then i try to un install it.. reboot and let windows search the driver .,... and everything is ok now

joeandmarg0 said:

Have you tried shutting down and disconnecting all the external drives,then reconnecting one at a time and checking bios recognition for each and likewise in Device manager?

There goes

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EnvioX said:

try uninstall all usb drivers ... and delete the driver (if the option available)

let w10 use their driver
and dont update using driver booster utilities or similar app to update driver.


i had same problem before... randomly disconnected my mouse and reconnect. then i try to un install it.. reboot and let windows search the driver .,... and everything is ok now

I mentioned in OP that I did exactly that .