@mdbirkett I also have the same problem.

Access control is set for read and write but I cannot write any file to the drive UNLESS I goto the FTP address in explorer as the manual shows.

Then I can drag and drop and it works.

But we need proper write access. If I map the drive to a letter I cannot write to it.

Also cannot write to the drive if I use a client to access it from Android. (pretty much any third party file explorer type app whether windows or Android only read works.

The only thing that works is if you access it by placing the FTP address in the address bar in windows explorer

Even if I disable sharing security and use no user or password, same issue arises. There must be some permissions still blocking complete access to the drive that we are unable to change in the settings.

Maybe TP-Link can update some firmware to give us more options for permissions and security of USB storage. 

@Malleable;

I was able to resolve my issue by reformatting the drive NTFS and starting from scratch.  Since doing this, I have not had any issues accessing the drive using a drive letter. 

@mdbirkett 

Thanks for that, I'll have a go at reformatting fresh rather than using an already full drive.

I'm already formatted for NTFS though. I read on another post the TP -Link said NTFS wasn't supported for write access so I was going to try FAT32 but now you've confused me. 

@mdbirkett 

Funny enough, I just logged in to have another look and I just dismounted it in the software using the little eye next to the drive, then mounted it again and hit refresh

Low and behold I was able to write to it instantly, no formatting.

For those struggling, you should try toggling the eye (next to the drive)  

@mdbirkett 

I am having the same problem.  I also tried the clicking on the 'eye', but I still got a "You need permission to perform this action".  I then tried the trash can, then scanned for the drive, and I was able to copy a couple of files before I ran into the same issue on the 3rd file.

The drive is a 5TB WD, formatted exFAT.  It was previously formatted in HFS+ and attached on a different router.  The AX11000 reads HFS+, but only when formatted from a more recent MAC OS system.  It didn't read a HFS+ from a 10.7 OS.

So I reformatted the HD, started copying from the backup, and it seemed that it got through half the files, and then judging by the logs, lost write permission to the drive.

@mdbirkett 

After re-formatting the hard drive twice, one with Windows 10 and the other Windows 7, both with exFat, I still got permission errors at some point while copying back from back-ups.

NTFS does work, as that's the back-up drive format.

But I need this drive to be able to be used on some Macs, so I ended formating the drive in HFS+, but I reformated the drive on a more recent Mac OS.  I haven't had any issues since.

@Malleable This also worked for me, and has no logic. Because that little eye is to see the Password with characters and not just *****
But it worked lol, thank you