Unmountable Flash Drive, CHS Mismatch

[dizzy51413]

On a debian system, if I copied files that were owned by root without chmod to all first onto a flash drive, would that cause the flash drive to become unmountable?

If so how would I go about recovering the data that was on the drive?

 

[B00nie]

On a debian system, if I copied files that were owned by root without chmod to all first onto a flash drive, would that cause the flash drive to become unmountable?

If so how would I go about recovering the data that was on the drive?

it shouldn't. Possibly you didn't eject the drive before unplugging it and it got corrupt? In any case, try mounting it as root. If it still doesn't work it's not a permission issue but something else.

 

[dizzy51413]

B00nie I am meticulous about unmounting external media prior to ejection. The first two times this happened I thought it may have been a permissions issue, but now I have 6 flash drives, from multiple manufacturers - all new, that give errors for either unmountable or input output error.

After the first 2 corrupted I started chmoding all files to a+rwx. Four more corrupted. All six of these drives contain text files and screenshots (and a few pcapng) documenting a hack I'm trying to mitigate.

If I run file -s the output for all of them shows a CHS (cylinder head sector) mismatch. Two of them also say missing operating system, even though none was installed.

On one of them I tried repairing it with NTFS-3g and testdisk and it only made it worse. Now the partition is missing.

All but one drive are NTFS, one is Fat32.

Any suggestion on what to try next would be greatly appreciated.

 

[B00nie]

B00nie I am meticulous about unmounting external media prior to ejection. The first two times this happened I thought it may have been a permissions issue, but now I have 6 flash drives, from multiple manufacturers - all new, that give errors for either unmountable or input output error.

After the first 2 corrupted I started chmoding all files to a+rwx. Four more corrupted. All six of these drives contain text files and screenshots (and a few pcapng) documenting a hack I'm trying to mitigate.

If I run file -s the output for all of them shows a CHS (cylinder head sector) mismatch. Two of them also say missing operating system, even though none was installed.

On one of them I tried repairing it with NTFS-3g and testdisk and it only made it worse. Now the partition is missing.

All but one drive are NTFS, one is Fat32.

Any suggestion on what to try next would be greatly appreciated.

Ah, you were using NTFS. NTFS-fuse / NTFS-3G are not totally reliable, they're more of a band-aid to help dealing with Windows. IIRC ntfs-fuse documentation recommended to avoid writing using it. Having said that I haven't had such problems personally so could it be possible that there's something haywire with your usb ports/mobo?

Sometimes a corrupt ntfs stick requires a repair using real windows, then it works again. But this scenario usually manifests when unsafely removing the stick.

 

[dizzy51413]

But this scenario usually manifests when unsafely removing the stick.

B00nie I have been primarily running linux boxes for a decade. Occasionally I have to move data between linux installs and a Windows VM, so I have always left flash media as the default NTFS they come preformatted as. I have never had this problem until I was dealing with a nasty hack.

This is not limited to only one machine either. Most of my workstations run Debian, but my primary machine runs Fedora. I was slowly backing up all the data on my flash drives to an external HDD connected to Fedora. The last time I did it, all data copied successfully, I unmounted both the flash and the HDD and shutdown the system. When I rebooted the next day both flash and HDD showed input output error and refused to mount.

Could you speculate on how these errors would be caused intentionally?

 

[dizzy51413]

Ah, you were using NTFS. NTFS-fuse / NTFS-3G are not totally reliable, they're more of a band-aid to help dealing with Windows. IIRC ntfs-fuse documentation recommended to avoid writing using it. Having said that I haven't had such problems personally so could it be possible that there's something haywire with your usb ports/mobo?

Sometimes a corrupt ntfs stick requires a repair using real windows, then it works again. But this scenario usually manifests when unsafely removing the stick.

B00nie Thanks for your input. Installed fresh copy of Windows on a workstation and was able to recover 95% of my data including my external HDD. All but two of the flash drives. Did find some peculiarities, but I'll save analysis for another thread.

If anyone has any suggestions for an application to recover corrupted data for the last two flash drives, both of which are missing the partition tables, would be greatly appreciated.

 

[B00nie]

B00nie Thanks for your input. Installed fresh copy of Windows on a workstation and was able to recover 95% of my data including my external HDD. All but two of the flash drives. Did find some peculiarities, but I'll save analysis for another thread.

If anyone has any suggestions for an application to recover corrupted data for the last two flash drives, both of which are missing the partition tables, would be greatly appreciated.

There is a cheap app called R-studio Windows that can recover formatted/corrupted drives. I've used it successfully. https://www.r-studio.com/