USB Falsely Ejected

I'm not completely sure what you mean by the USB being "physically seen" by macOS.

In Disk Utility you may need to click the "View" drop down list just above the left pane and select "Show all devices" before a physical drive may appear in the left pane. By default recent versions of macOS show only a volume view by default instead of the physical devices.

You can also use the Terminal app and the following command to list all of the drives & volumes seen by macOS:

diskutil  list

Look through the list to locate the USB stick (it should be the last entry if you plug the USB stick just before trying any of the above). Just give macOS a full minute before checking since USB sticks with hardware or compatibility issues may take longer to communicate with macOS.

If you don't see the physical USB stick listed with one of these two methods, then the USB stick has a hardware or compatibility issue with the Mac. You could always try to see if the USB stick physically is seen on another computer (even Windows in Disk Management -- just don't partition/format it). If it can be seen, then a clone or raw image of the drive could be made using Knoppix Linux and GNU ddrescue and then have the Mac try to mount the image or clone.

While these tools can possibly access and recover data, it is definitely easier to have a professional data recovery service do the work especially if you are not comfortable with the tools/utilities since the pros have more specialized tools.

If you were copying the files, then the originals should still be on the source drive.

If @TheLittles' first two suggestions don't work, but the USB stick is physically seen by macOS, then the next step would be to make a raw bit for bit clone of the drive. The command line utility "dd" can be used, but GNU ddrescue works better if the drive has physical issues. By cloning the USB stick and working from the raw image or the clone you don't further degrade the USB stick if you need to use a professional data recovery service such as Drive Savers or Kroll Ontrack both of which provide free estimates. You have to be extremely careful with these utilities since it is very easy to overwrite the data you are trying to recover.

PhotoRec and TestDisk are two free multi-platform utilities (Mac/Windows/Linux) for recovering data from a drive depending on the file system used on the USB stick. I've had TestDisk correct file system issues on a corrupt drive/image in order to allow the transfer of a file. TestDisk works without mounting the volume. You should work from the clone just to be safe since it is very easy to make a mistake.

Data Rescue is a paid app I used years ago.

Sometimes Disk Utility is needed to repair a file system even on the clone, but sometimes Disk Utility is unable to repair the drive and Disk Warrior may be needed to get the file system in state where the drive can be mounted.

There is no guarantee any app will be able to read or recover data from a USB stick. If cloning the drive and using the free apps don't work, I think it would be best to consult one of the professional data recovery services I mentioned earlier instead of spending/wasting money on apps that may not work.

If you might use a professional data recovery service, then please minimize doing anything beyond trying to use Disk Utility First Aid on the USB stick. If the data is critical, then don't even make any further attempts to mount the drive (or use Disk Utility) and consult a professional service so you don't make their job harder or even impossible.

sxs64 wrote:

Is there any way to fix the USB stick itself or extract the data from it? Or does the USB port have a problem?

To Retrieve/Extract the Data, Try...

• Restarting your Mac: Have you restarted your Mac? If not: shut down the Mac > wait 15 seconds > plug the drive into the USB port > power up the Mac. Does it now show?

• Using Disk Utilities to Mount the Disk: Go into Disk Utilities and see if you need to Mount the Disk. If it is blurred out, then right click on it, select "Show All Volumes", and see if the data can be accessed. You might have to run First Aid on the disk, if it is not mounting. See if that works.

• Getting the Drive Serviced: Note that data might have to be extracted from it, manually. Unless a protection of sorts was purchased on it somehow, extracting all the data might cost quite a bit. So, contact the manufacturer to find out what services are available to you, when it comes to extracting the data off of it.

sxs64 Said:

“...it may be that the USB is showing up elsewhere”

Try the following in the order provided...

Rid of Any Security Software:

Security Software is unneeded on your Mac, as parental controls and Firewalls would get in the way. So, uninstall it.

Once uninstalled...

1. Shut Down the Mac
2. Plug in the USB Drive
3. Restart Mac
4. Logon as the Administrator

Single this Out by Using Another Administator User:

1. Go To: System Preferences > Users and Groups > Click “+” on the bottom of the window > Create a new Administrator type User
2. Shut Down the Mac
3. Plug in the USB Drive
4. Restart Mac
5. Logon as the new Administrator

———

Mounting it through use of Recovery Mode. Note: if it is dimmed, then drive is has already been mounted.

1. power on your Mac,
2. immediately press and hold down Command-R
3. go to the Utilities window
4. select Disk Utility
5. click Continue
6. select this USB drive
7. select Mount from the menu bar.
8. type [the administrator password{
9. press the enter key
10. go to the File Menu
11. select Restart
12. restart the Mac
13. log in

———

Is this now seen and accessible in Libraries?

You’re welcome! 🙂. Nothing else really comes other than to research “out of the box compatibility.”

I’m just curious if Windows PC would show it, and not Mac OS If so, then compatibility would be getting in the way. Some USB drives, however, are compatible with both Windows and Mac OS — right out of the box.

So, if you were to find the manufacturer, email them the model and serial number, and ask them about compatibility, that may find just what you need. The Contact Us page would be under the services menu of the manufacture's home page, most likely.

If this were reformatted to just Mac OS, then it would not be readable with Windows, and vicé versa.

Find out more here: File System Types

The Littles Said:

”If this were reformatted to just Mac OS, then it would not be readable with Windows, and vicé versa.”

and...

HWTeach Said:

“Windows and Linux are usually a little more forgiving when hardware or file system issues are involved.”

———

Thank you for the reply. To make myself clear, I am referring to the reformat of an “Out of the Box”-purchased USB Drive that comes formatted with compatibility for both Windows and Mac.

So, after a reformat to Mac-Compatibly, it would be dedicated to Mac, whereas after a reformat to Windows-Compatibly, it would be dedicated to Windows.

This would do away with the “forgiving” part, as you put it.

TheLittles wrote:

The Littles Said:

”If this were reformatted to just Mac OS, then it would not be readable with Windows, and vicé versa.”

and...

HWTeach Said:

“Windows and Linux are usually a little more forgiving when hardware or file system issues are involved.”

———

Thank you for the reply. To make myself clear, I am referring to the reformat of an “Out of the Box”-purchased USB Drive that comes formatted with compatibility for both Windows and Mac.

So, after a reformat to Mac-Compatibly, it would be dedicated to Mac, whereas after a reformat to Windows-Compatibly, it would be dedicated to Windows.

This would do away with the “forgiving” part, as you put it.

Ok, I wasn't completely sure how you meant it now that you have clarified about the "out of box" formatting. I agree that reformatting the drives is always a good idea. I always reformat any pre-formatted drives just to be safe even if I put the same file system back on it.

By the "forgiving" part I mean if something happens to the hardware or the file system such as being corrupted, that Linux (and sometimes even Windows) will be able to do more or provide more information than macOS. Personally I find macOS is terrible for troubleshooting the majority of issues.

If someone wants to access a drive across multiple operating systems, then it is best to format the drive using macOS and exFAT since once again Windows and Linux are able to handle a broader range of formatting options than macOS. FYI, macOS is currently unable to read some Windows formatted exFAT drives because Windows is using a block size macOS does not understand.

@TheLittles, I've seen Macs be very particular about the USB sticks even with name brands. For some reason they don't always show up properly especially if something odd happens to the drive or even file system/partition. I know it does not make any sense, but I've seen this happen more than once. No name brands and cheap USB sticks are even worse.

While the OP won't be able to actually read the USB drive from Windows (without third party paid software), at least it is way of testing whether the USB drive physically shows up and is still functional. Windows and Linux are usually a little more forgiving when hardware or file system issues are involved.