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Summary: Don't know how to fix when USB flash drive is not mounting on Mac? Try these 4 solutions in this page and use iBoysoft Data Recovery for Mac to recover lost data necessarily.

1. Apple Usb To Serial
2. Best External Hard Drives For Mac
3. Usb Drive For Macbook Air
4. Usb Drive For Macbook Pro
5. Usb Drive For Mac And Pc

The 1st third party software which can create bootable USB is TransMac. Basically, it is not an open source software, it has the trial of 15 days. After 15 days you won’t be able to create bootable USB for Mac with TransMac. So, try to find a portable software of TransMac. Change the USB-to-Mac connection way. Have you tried to restart your Mac once or twice? Edit your preferences. Hopefully there is a really easy fix to get the hard drive to mount on your. We will go over how to use a USB drive, thumb drive, flash drive, pendrive, etc, on a Mac computer (aka Apple Macintosh) like a MacBook Pro, iMac, Mac Mini. If you want to use your USB stick with an Apple Mac, you will need to restart or power-on the Mac with the USB stick inserted whilethe Option/alt(⌥)key is pressed. This will launch Apple’s ‘Startup Manager’ which shows bootable devices connected to the machine. Your USB stick should appear as gold/yellow and labelled ‘EFI Boot’.

When I plugged in my USB flash drive on macOS High Sierra, I can't see it in Finder or on the Desktop. So, I went to Disk Utility, it was there. But the USB flash drive was grayed out in Disk Utility and I could not mount it. How can I fix/repair USB flash drive not mounting issue on Mac?

It is user-friendly that Mac will automatically mount the inserted USB flash drives. However, if the USB flash drive is not mounted on Mac, you will lose access to the USB flash drive as well as to the data stored on it. But don't worry, this page talks about the reasons for this issue, and how to fix 'USB flash drive not mounting on Mac' without data loss even if external hard drive is not showing up on Mac.

Why the USB flash drive is not mounting on Mac?

What makes the hard drive not working problems like USB flash drive unmounted on Mac can be various. This is because that this external drive is connected to the Mac computer through USB cable, USB port and many other components. The possible reasons for this issue include:

• Faulty connections like broken cable and wobbly USB port
• File system errors, volume header corruptions, etc. in the USB flash drive
• Disk Utility failure, log file corruption, OS malfunction on this Mac
• Physical damage and other factors

How to fix/repair USB flash drive not mounting issue on Mac?

No matter what results in unmountable USB flash drive, it's urgent to fix/repair USB flash drive not mounting issue on Mac. Here are 4 solutions to this unmounted USB flash drive issue according to different causes, you can check them one by one.

Solution 1: Check the USB flash drive in System Information

If you plug this USB flash drive into your Mac computer but get no sign that this drive is mounting on Mac, you can check System Information to see if this USB flash drive is showing up.

1. Step 1: Go to Utilities and choose System Information.
2. Step 2: Double-click on its icon to open it and choose USB in the left sidebar.
3. Step 3: Check if your USB flash drive is detected by the system in the right box.

If your USB flash drive is not showing up in the right box, you can try to re-plug it, or change another USB port and cable to connect it.

Solution 2: Check the Finder Preferences

Sometimes, you just can't find the USB flash drive in Finder and on the desktop, but actually, it is mounted on your Mac and just not showing up. Check the Finder Preferences and see if it will appear.

1. Step 1: Click Finder and choose Preferences in the top menu bar.
2. Step 2: Check External Disks in General tab so that the USB flash drive can be shown on the desktop.
3. Step 3: Go to Sidebar and check External disks so that they can be located in Finder.

Solution 3: Check and repair this USB flash drive with Disk Utility

If you still can't access your USB flash drive thereafter, you can go to Disk Utility which is a built-in utility to fix disk problems. If it is greyed out in Disk Utility, you can manually mount this USB flash drive.

1. Step 1: Go > Utilities > Disk Utility.
2. Step 2: Click on View option and choose 'Show all devices'.
3. Step 3: Click on the name of your USB flash drive.
4. Step 4: Select Mount in the upper menu bar.

If the Mount button is greyed out and you can't mount this USB flash drive manually, then there could be some disk errors. Fortunately, you can use First Aid in Disk Utility to repair this unmountable USB flash drive.

1. Step 1: Launch Disk Utility.
2. Step 2: Choose the grayed-out USB flash drive.
3. Step 3: Select First Aid in the top center and click Run.

Solution 4: Fix the unmountable USB flash drive by reformatting

However, if Disk Utility fails to repair this external drive because of serious file system corruption, you can only fix this by reformatting. The thing you need to keep in mind is that reformatting will erase all files on this USB flash drive, which means, you need to make sure an existing file backup. Or you can recover lost data from the unmountable USB flash drive before you fix the USB flash drive not mounting issue on Mac by reformatting.

How to recover lost data from unmounted/unrecognizable USB flash drives?

Can't open the unmountable USB flash drive but don't want to lose data? You can still get your files back with USB flash drive data recovery software before you reformat this drive.

As one of the most professional USB data recovery software, iBoysoft Data Recovery for Mac is highly recommended. It can recover lost data from unmountable, unreadable, and corrupted USB flash drive, recover deleted/lost files from emptied Mac trash. Moreover, this software performs well in recovering data from hard drives, external hard drives, flash drives, USB sticks, SD cards, and other storage devices. Data recovery is allowed on macOS 10.14/10.13/10.12 and Mac OS X 10.11/10.10/10.9/10.8/10.7.

Step 1: Recover lost data from unmountable USB flash drive with Mac data recovery software

1. Step 1: Download and install iBoysoft Data Recovery for Mac on your Mac.
2. Step 2: Connect your USB flash drive to the Mac and launch iBoysoft Data Recovery for Mac.
3. Step 3: Select the unmountable USB flash drive and click 'Next' button to scan all lost files.
4. Step 4: Preview the scanning results by double-clicking, choose files that you want to recover, and click 'Recover' button to get lost data back.

Apple Usb To Serial

Note: In case you lose the recovered files again in the next reformatting step, you'd better save these files to another reliable drive.

Step 2: Reformatting this USB flash drive without data loss

After recovering data from this unmountable USB flash drive, you can reformat this USB flash drive without worrying about losing anything important.

1. Step 1: Go > Utilities > Disk Utility.
2. Step 2: Click the icon of unmountable USB flash drive on the left part of the window.
3. Step 3: Click the Erase button on the top of the Disk Utility window.
4. Step 4: Complete the related information(name, format, scheme), then click Erase button.

When the process finished successfully, your USB flash drive will be mountable on the Mac computer again. But the case is, no matter how powerful USB flash drive data recovery software is, the best way to recover files from external drives is to recover them from backups. So, remember to duplicate your files this time.

You may also want to know:

HSD not mounting or seen in Disk Utility? Tutorial to fix SD card not mounting on Mac and recover lost data from unmountable SD card on macOS.

Every operating system can crash at one time or another. While it's safe to say that macOS is more stable than Windows, it can still be affected by issues that prevent your computer from booting up. In such cases, you might need to boot your Mac from a USB flash drive to fix the problem. This article shows you two ways to boot Mac from external USB stick, as well as some troubleshooting tips in case Mac won't boot from the target USB.

Boot Mac from USB Option l: Startup Manager

If your Mac won't boot up normally, you can set it to boot from a different drive, such as a USB stick containing macOS installation files in bootable format. The drive will have to contain a version of the OS that is compatible with the Mac. As long as you have the bootable installation USB, you can start your Mac from the USB by accessing the Startup Manager. Here are the steps to be followed:

Step 1: Insert the bootable USB into Mac and power it on.

Step 2: As soon as the startup process begins, hold down the Option (alt) key and keep it depressed until you see the Startup Manager on your screen. If there is a firmware password on your Mac, hold down the Option key until you're asked to enter that password.

Step 3: You will now see the various startup disk options, and your USB will be listed there. If you click on the Up arrow right below the icon for the USB, the computer will only startup once using this disk. If you press and hold down the Control key while making your selection, it will be saved, and your computer will boot from the USB every time, as long as it is left in the computer.

Best External Hard Drives For Mac

At this point, you can also use the Mac installation disk to boot your Mac from. It will appear as EFI Boot, and it works on all computers running macOS 10.9 or higher.

Boot Mac from USB Option 2: Safe Mode/Recovery Mode

Usb Drive For Macbook Air

As an alternative, you can start your Mac in Safe Mode (Recovery Mode). This will allow the system to automatically detect and repair directory issues. Safe Mode will only allow required kernel extensions to load, preventing login items and startup items to load automatically. It can also help you isolate the issue depending on whether or not the issue goes away in Safe Mode. If the issues you have during normal startup don't show up in safe mode, they are most likely fixed. That means you can reboot normally and your system should be back to normal.

Step 1: Start your Mac and hold down the Shift key. You will see the Apple logo on your screen.

Step 2: When you see the login screen, you can release the Shift key and login to your Mac.

Usb Drive For Macbook Pro

Step 3: To check whether your Mac has booted into Safe Mode, click on the Apple logo on the top left and then on About this Mac. In the window that opens, click on System Report… You should be able to see this:

How to Fix Mac Won't Boot from USB Drive

Sometimes Mac won't boot from USB as expected. If you are unable to select a different startup disk, it's possible that your disk is not showing up in Startup Manager. If you try Method 1 above but don't see your USB drive listed there, it could mean one of the following problems:

Compatibility: It is possible that the version of macOS or Mac OS X that you have on the USB drive is not compatible with the hardware. That means you won't be able to see it in the Startup Manager so, of course, you won't be able to boot from it. In such cases, you may need to burn a compatible macOS version on USB drive in order to be able to boot Mac from it.

Startup Security Utility: In certain cases where your Mac has the Apple T2 Security Chip (2018 and later devices), it may be your Startup Security Utility settings that are preventing you from booting from USB. In this situation, restart your Mac and hold down the Command + R keys when you see the Apple logo. This will put your Mac into Recovery mode. In macOS Utilities, go to Utilities >Startup Security Utility and sign in as admin. Under External Boot, select the second option - Allow Booting from External Media.

Usb Drive For Mac And Pc

Option ROM Firmware: Another known issue is that Option ROM firmware will not load in Startup Manager until you press certain keys manually. To do this, use Method 1 to access Startup Manager. Once you are there, press Option-Shift-Command-Period. You should now be able to see the USB drive. This is not exactly a problem as much as a feature. If the USB contains Option ROM firmware, you will need to press those keys everytime to boot from your pen drive.

These two methods and the troubleshooting tips should allow you to boot from USB or in Safe Mode so you can then isolate the problem that's preventing your Mac from booting up normally.