There are many factors that can cause a USB disc to be unreadable by a computer. This could be due to a hardware problem or a corrupt partition. Fortunately, you may still be able to extract files from an unreadable disc, and there's a good chance that you will format the disc so that it can be reused.
Step
Part 1 of 5: Performing Basic Troubleshooting
Step 1. Plug the USB disc into another USB port
There could be a problem with the USB port you're using, so try plugging the disc into a different USB port on your computer. Do not use a USB hub to connect the disc; plug the disc directly into the computer.
Step 2. Plug the disc into another computer
If the USB disc is working normally on another computer but cannot be read on your computer via any USB port, there is a problem with your computer's USB hardware or drivers.
- Click here for a detailed guide to installing a USB expansion card.
- Click here for a detailed guide on updating USB drivers.
Part 2 of 5: Checking Disc Health
Step 1. Open the Disk Management tool
You can access this tool from the Control Panel, but the easiest way to do this is to press Win+R, then type diskmgmt.msc.
Step 2. Find your USB disc
The easiest way to identify your USB disc is by looking at its size. USB disks are generally much smaller than hard disks.
If the USB disk does not appear in the Disk Management list, there is a high possibility that there is a hardware problem with your USB disk or USB port. Click here for a detailed guide on repairing a physically damaged USB disc
Step 3. Check the USB disk partition
In the frame at the bottom of the Disk Management window, you'll see all the connected disks with their respective partitions to the right of each disk. Your USB disk partition should be in state Healthy.
- If the USB disk partition is in the state Healthy but it is not legible, you must provide a drive letter on the USB disc.
- If the USB disk partition is in the state Unallocated, you must format the USB disc.
Part 3 of 5: Giving Marker Letters to USB Discs
Step 1. Right-click on the USB disk partition in the Disk Management tool
If your disc is healthy but Windows can't read it, it's possible that the disc doesn't have a font yet. All connected discs require a letter marker for the system to read and write to them.
Step 2. Select "Change Drive Letter and Paths", then click
Add….
Step 3. Select "Assign the following drive letter", then select a letter from the drop-down menu
You will not be able to select letters that have been assigned to other discs. Do not choose the letter "A" or "B" as a marker.
If you still can't access the disc after providing the bookmarks, you should try to format the disc
Part 4 of 5: Formatting a USB Disc
Step 1. Right-click on the USB disk partition under Disk Management
If your disk partition is unallocated or you can't see it even though you've specified a letter, the only possible option for the disk to work normally is to format it.
Formatting the disc will erase all of the information on it, so it's best if you run a file recovery program on an inaccessible disc to try to save the important files
Step 2. Select "Format" from the menu that appears when you right-click on the disc
Step 3. Select "FAT32" as the file system
Although FAT32 is a rather old file system, it has the highest compatibility with almost all devices that support the use of USB disks.
If you plan to use only discs on Windows computers, select "NTFS" as the file system
Step 4. Uncheck the "Perform a quick format" box
Doing so will take longer to format, but it can help fix errors on the disc.
Step 5. Click
OK and wait for the formatting process to finish.
You should be able to access the disc on any computer if the formatting process is successful.
If the format process fails, your USB disk is most likely damaged
Part 5 of 5: Opening Formatted USB with Mac on Windows
Step 1. Download HFSExplorer
HFSExplorer is a free tool that allows you to browse USB contents with the HFS+ file system (Mac OS Extended file system). This file system can only be accessed normally by a Mac. HFSExplorer allows you to browse the contents of USB discs with the HFS+ file system using a Windows computer.
Step 2. Run the installation file and follow the given prompts
Start the program after the installation process is complete.
Step 3. Click the File menu, then select "Load file system from device"
Step 4. Select the USB disc from the list of connected discs
You can only load USB discs that have the HFS or HFS+ file system format.
Step 5. Select the files you want to copy
Once the USB disc has finished loading, you should be able to see all the directories and files contained in it. Select the file you want to copy to your computer.
Step 6. Click the "Extract" button
You will be asked to select a location to save the file on your computer. Once you've determined the save location, you can start copying files.
Step 7. Wait for the data copying process to complete
This process may take some time, depending on the size of the file you are moving. Once the copying process is complete, you will be able to access the files from the location you selected earlier.