Dropbox Files Cannot be Copied to Samba Share

[kaletana]

Hi all,

I am encountering a very weird issue when trying to copy files in my Dropbox folder to my Samba share.

OS: Windows 10 Home
TrueNAS: TrueNAS-13.0-U4

I have Samba dataset mapped as a network drive and when I try to copy (with File Explorer) any file in my Dropbox folder to any folder in the mapped drive, I get "Destination Folder Access Denied" error so the copy is not successful. With Robocopy, I get ERROR 5 "Access is denied". I have tried following to narrow down the issue.

• It only happens to the files in Dropbox folder and files in other folders (such as OneDrive or GoogleDrive) can be copied without issues.
• If I copy a file in Dropbox out to another folder and even make some modification to it, it still cannot be copied to the Samba drive
• If I copy a folder with files in Dropbox to the Samba drive, the files cannot be copied but the folder is made. However I cannot delete the folder as I get error of "the folder is open in another program". I can only delete the folder after I restart my PC.
• If I copy a file in Dropbox to a FAT USB drive, presumably stripping its NTFS specific properties, it can be copied to the Samba drive
• If I 7-zip the files in Dropbox and try to extract them to Samba drive, I get complaining of "Cannot set file attribute: Access is denied" from 7-zip but the files end up actually extracted into the destination
• If I copy a copyable file into Dropbox, it becomes uncopyable to Samba drive after it is sync'd
• My original ACL for the Samba dataset was Full Control for @owner and Read for @group and @Everyone. I have tried giving Full Control to @group and @Everyone but it did not make any difference
• The issue seems to happen recently as I have been able to sync a lot of files between Dropbox and samba drive in the past
• I have compared the ownership and permissions of copyable and uncopyable files and could not find difference
• I have tried changing the permission of every user in an uncopyable file property to Full Control but it did not make any difference

I am running out of ideas now. It seems to me that when Dropbox is syncing its files, it makes changes to some file properties invisible to me but the changes perhaps cause Samba to see them as owned by unauthorised user. Any help, insights and tips will be appreciated. Thanks in advance.