External Drive - bad clusters

[glucke]

Hoping for advise on using Terminal to check my external hdd.
The usb drive is formatted to exfat and is used to move files between mac and windows computer.
A particular folder on the drive, whilst visible will no longer open either on my mac or windows pc. I tried to repair the drive using DOS commands on the windows pc and this resulted in a notification that the drive has bad clusters.
I would like to attempt a similar repair using the Terminal on mac in the hopes that this might fix the problem.
Research that I have done suggest using a command diskutil repairDisk /dev/disk?
Any other suggestions, help as to how I can fix this problem would be appreciated.
I do realise that I should have made a back up of these files but all I can say is some lessons are learnt the hard way !

Thanks in advance

 

[Randy B. Singer]

Which version of the Mac OS are you running?

Is there some reason that you prefer to use the command line?

 

[glucke]

Which version of the Mac OS are you running?

Is there some reason that you prefer to use the command line?

Hi,
Its Catalina 10.15.7 OS
I have more knowledge of Windows than Mac and have just presumed that I would need to use specific commands to do a deep investigation of the drive.
If other options are available that could possibly repair this error I will definitely try that route.

 

[Randy B. Singer]

To my knowledge, there are no repair routines that you can run from the command line beyond what is available using Apple's (included with the Mac OS) Disk Utility. However, if you insist on using the command line you will need to do so booted into a special mode:

- Startup your Mac into Single User Mode by holding down Command+S during startup.
- At the prompt type in:
fsck -fy
- Keep on running FSCK until you get: "The volume (name) appears to be OK"
- Type:
reboot
...to leave Single User Mode.

See:

How to repair a Mac storage device with Disk Utility
How to repair a Mac storage device with Disk Utility - Apple Support

What concerns me is your use of exfat. I don't know how effective Disk Utility is with disks formatted as exfat.

I had hoped that you would have the option of using the commercial product Disk Warrior, which can often perform miracles, but unfortunately it doesn't work with exfat formatted disks:

Disk Warrior ($120)
ALSOFT - Makers of DiskWarrior.

 

[ferrarr]

Can you format it as NTFS on winOS, then back to exFAT?

 

[glucke]

To my knowledge, there are no repair routines that you can run from the command line beyond what is available using Apple's (included with the Mac OS) Disk Utility. However, if you insist on using the command line you will need to do so booted into a special mode:

- Startup your Mac into Single User Mode by holding down Command+S during startup.
- At the prompt type in:
fsck -fy
- Keep on running FSCK until you get: "The volume (name) appears to be OK"
- Type:
reboot
...to leave Single User Mode.

See:

How to repair a Mac storage device with Disk Utility
How to repair a Mac storage device with Disk Utility - Apple Support

What concerns me is your use of exfat. I don't know how effective Disk Utility is with disks formatted as exfat.

I had hoped that you would have the option of using the commercial product Disk Warrior, which can often perform miracles, but unfortunately it doesn't work with exfat formatted disks:

Disk Warrior ($120)
ALSOFT - Makers of DiskWarrior.

Thanks for this advise I will follow the link to Apple Support.

 

[glucke]

Words of wisdom will be observed moving forward and in this instance it is clearly the fool to blame.

 

[pm-r]

I had hoped that you would have the option of using the commercial product Disk Warrior, which can often perform miracles, but unfortunately it doesn't work with exfat formatted disks:

Wow, I haven't heard the name of the wonderful DiskWarrior application mentioned for a long time and it seems that it pretty well got killed off with apples introduction of their APFS formatting structure.
But it seems it can still be used for rebuilding volumes in other formats including external disks from what their support site says.

But it's also a bit expensive for the average user to invest in and I guess I'll never know if they ever improved their upgrade routine which was a real PITA with their older upgrade versions.

Anyway, its usefulness has certainly been reduced compared to what it used to be. Too bad.

EDIT:
If the OP wants to check or possibly repair the questionable Drive and it's problems they may want to have a look and give TechToolPro or maybe even Cocktail applications a try.

I have never tried using cocktail but Tech Tool Pro has been a handy tool to have where other software has given up working:

Using Techtool Pro for Mac drive repair - Micromat

If your Mac is running slowly, crashing, or just generally misbehaving, the problem may be your disk. Both solid state and rotational hard drives can be the most error-prone components in your Mac. Slow performance, sudden application crashes, even computer crashes can be attributed to a...

www.micromat.com

- Patrick
=======

 

[Rod]

Fat32 is better than ExFat I have found for "transfer" disk's used between the two platforms.
By all means try Disk Utility First Aid, it is as far as I can tell the same as the Terminal command described by Randy. I would have expected that a repair program on the PC would have been more suitable.

 

[ferrarr]

Fat32 is better than ExFat I have found for "transfer" disk's used between the two platforms.

I agree,. I only use exFAT for large files (over 4GB).