I have a USB flash / thumb drive. It works on a Windows 10 pc but not on my Linux-Ubuntu 16 pc - - - it does not register when I plug it into the USB port and the Ubuntu "Disks" utility does not detect it. I have tried to make sense of some of the replies already given to similar questions ("Click Here to Find Similar Threads") but none of them make any sense to me - I am a terrible noob! Suggestions would be greatly appreciated.
Duncan

Have you run "dmesg" from a command prompt before and after plugging in this USB stick?

That will dump the system log, before shows a bunch of stuff, but it shows you (at the end) the latest events, so you know where it last stopped.

After shows you all from before, plus (maybe) some additional events that occurred when you plugged in the USB stick.

Please check that and see if your system log sees anything in the USB when you plug in your stick.

By the way, is this PC the same one when it is W10 and Ubuntu? I.e. are you performing dual boot? Or are these separate PCs?

And also, are you using a virtual machine, by any chance? There are issues using USB through virtual machines, you may have to install additional software, or make some configuration option changes.

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Hi RTMistler - many thanks for your reply. No, the last lines of the "dmesg" command are identical:

[20397.316911] usb 3-4: USB disconnect, device number 2

I had a USB ext hard drive attached - I think that is what is being referred to here. But this shows up every time I run the "dmesg" command - both before and after I insert the thumb drive.

Oh, and no, the Windows 10 is on a different computer - my wife's. So, no dual boot and no virtual machine.

It seems as if it does not recognize this USB stick at all.

From there I would diagnose hardware.

If that one port ever works with anything.

If there are other ports on your system where you see this same behavior.

Thanks for your response.
1. The USB stick works on my wife's Windows 10 pc
2. The USB port on my pc (Linux Ubuntu 16) on which this particular USB stick wont work (i.e. is not detected) is fine for other USB devices, including other USB sticks.
3. I have tried the USB stick on all USB ports (on my Linux pc) and it does not work in any of them.

I suppose I could come at the problem from another angle - how can I mount a USB stick that is presently not recognised?

Duncan

You can't mount something that is not seen to be a hardware detection. End of story, at least as far as I know. If you system log does not note that something was plugged in, then you can go no further.

Any idea what file system type is on that disk? Is it an out of the box USB stick? From which manufacturer?

Next would be:
What are the system specifications for your Ubuntu PC? Is it some manufacturer's existing model? Or a home made PC?

And if you haven't already looked, I invite you to examine the changes to your system log when you do plug in something that does work. It seems as if you already have. And thus you potentially can see that there would be no way or direction to follow to issue a mount command. Because the format for a mount command would be:And it is the <physical resource location> which you do not have and cannot resolve. I.e. when you plug in a working other drive that mounts itself, it may be on something like /dev/sdb1, or /dev/sdc1, or /dev/sdf1 and the main location of hardware is /dev/sd[letter]. If you had that, then you could run fdisk, or even fdisk -l on that drive letter. Sure, you can run fdisk -l in general to get a report on all drives. Perhaps that's worth trying to see if somehow the system sees that drive without it putting stuff in the system log, for some odd reason.

And finally, please make sure that your Ubuntu system has been rebooted at some point. Perhaps it has some odd system state, although Linux typically has done the due diligence to ensure that this does not happen, and a reboot may clear it up. Another thing to consider is to ensure that your system is up to date. But that's questionable to consider. This should work now, not merely because of any software updates.

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1. Many thanks for your patience - I really appreciate it.
2. For a noob, you have given me a lot to tackle - I will do it slowly over the next day or so.
3. In the meantime perhaps the following information may help:
4. It is a new USB stick - it worked at first. I then wanted to encrypt it and used the "Disks" utility to try to do this. Ever since then it has not worked. So, during this process I think I must have wiped something from the stick - some sort of basic code (? BIOS) that was there. I suppose we should now treat it as a totally blank stick - is it possible to put this basic (background) stuff on it - probably something to do with a boot file?
5. Now, I know the simple answer is to chuck the USB out - it was not expensive and I have others - but I'm up for the challenge of getting it to work again and I believe this will help me learn linux commands!

Thanks once again for your patience - really appreciated.
Duncan

Please excuse anything that may offend here

My very long time friend, who is Jewish, and we're talking American Jewish, and joking about stereotypes, etc. He would do that old man's Jewish sounding "Ah-cz-haa!" and wave his hand in the air. (In the funny after scenes from the movie Coming to America, the barbershop scene, is one example.)

Yes, #4 seems highly suspect.

I do have to say, I see a ton of questions where somebody has a problem because they did an install and encrypted the whole thing and now nothing works. I also have to say, that it seems that encryption is a dicey thing, that perhaps should not be so dicey for new users. I don't know how to alleviate that, I'm by no means an expert.

Proposed solution:
Since you can "see" this disk using your wife's W10 computer, then fully reformat it, not a quick format, using that computer, and then continue. I do not feel you can fix it under Linux because you can't see the drive at all.

If you choose to try again, perhaps start a new question, noting a link to this one, and then citing the instructions you followed, as well as any different ones you next intend to try, and ask if there's any additional advice.

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I found a solution to my problem and, good news, it is simple!
1) To recap, a thumb-drive (USB-stick) could not be detected on my linux pc (Ubuntu 20.04) after formatting (full format). Could not be detected by the GUI File-manager, nor via the number of possible terminal commands.
2) The thumb-drive (TD) was detected by my wife's Windows 10 laptop.
3) I proceeded to do a simple format of it (the TD) (on the Windows laptop) - and also selected the "restore to defaults" option before the simple format to 32 FAT. After this formatting, the TD was able to be detected by my Ubuntu machine and it is again functional.
HAPPY DAYS!
=================

Duncan49,

It may be a good idea to use Linux Mint 20 since support for Linux Mint 16 ended in July 2014.

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Note to RTMISTLER: many thanks for your help and patience - greatly appreciated.
Sincerely
Duncan

Thanks for the tip BB2 - re Mint-20

You must partition a drive before formatting it, that's probably what happened (what your wife's win10 did). There are GUI on your ubuntu for doing this.

Also it should be "recognized" as a device without partitions but not as "a disk". But the GUI utility your using is probably rudimentary and does not go into such detail.

as for if your a noob, we plan to ask your wife, since we can't judge that here

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I suspect your entire problem was due to the attempt to encrypt the USB stick. Either it was actually encrypted or it failed and wiped the partition table off the drive without creating the new table. Your recreating the default table on windows recovered it (yes, sometimes windows can do things linux cannot, although seldom).

Thanks for the update and solution.

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Thank you both, 'X-LFS' and 'computersavvy'.
This is interesting information - that a thumb-drive should be partitioned before formatting it. I suppose this is to preserve the boot section of it.
So, in future, before formatting I should create a partition so that there will be the boot partition and the newly created partition that will actually be used. One could of course use 'GParted' to make the partition.
Thanks once again for your time and expertise.