When you created the shared folder on Windows, you had the opportunity to change the default permissions on the share (which grants Everyone read-only access). You should go back to the share properties, and click on Permissions and grant Full Control permission to one or more Windows users known to your machine. Or you can give Everyone Full Control (but be careful what data you expose).

When you access the share from another machine (even a Mac) you should be required to authenticate with the Windows machine, at which time you would enter a username/password for a user known to the Windows machine. Then you will have write access.

The problem here is that terminal is trying to write Unix style permissions to the CIFS share during the copy operation.

When you perform "cp" via terminal the data will transfer but the fchmod command will fail as the "core CIFS protocol does not provide unix ownership information or mode for files and directories".

A few solutions:

• Mount the share via command line and engage the noperm option to ignore permission errors.

  mount_smbfs -o noperm "//DOMAIN;[email protected]/blah" /Volumes/blah
  

• Alternatively you can use rsync to copy files (without the -a flag)

  rsync -rl source destination.
  

Source: https://www.samba.org/samba/docs/man/manpages-3/mount.cifs.8.html

Usually the authentication prompt is in relation to the destination for your copy.

Thus, from what you're describing, you should enter your Gentoo login credentials. However, I suspect the owner/write permission are too restrictive on that specific volume. Have you checked owner user/group on the problematic volume vs. the other "problem-free" volumes? Are the read/write permissions the same?

To change the permissions without resorting to Terminal, highlight the folder you want to put the user file in and select Get Info (Cmd+i). At the bottom are the permissions. Make sure that where it says "everyone" that it also says "Read & Write." You may have to click the little gold lock at the bottom of the Get Info pane to adjust this. Once you do this, you will be able to copy your folder over.

When an app or process can't access an external drive, the Desktop and/or the Documents folder, it is usually due to missing permissions in System Preferences > Security & Privacy > Privacy > Full Disk Access.

Now, you would expect that starting file sharing would automatically grant the SMB server process the appropriate permissions, but that doesn't seem to always be the case.

Fortunately, you can easily set it up yourself:

1. Open System Preferences and open Security & Privacy > Privacy.

2. If the pane is locked, press the lock and enter an administrator's name and password.

3. In the sidebar, select Full Disk Access.

4. Press the + button.

5. Press ShiftCommandG and type /usr/sbin.

6. Select smbd and press Open.

7. Make sure smbd is enabled:

   

8. Close System Preferences.

Looks like you created a folder miguel in the media and you have taken ownership of it. Instead, let's create a group, add users to that group, and set the permissions.

sudo groupadd -g 10000 [samba_group]
sudo adduser migeul [samba_group]
sudo chown root:[samba_group] -R /media/migeul
sudo chgrp [samba_group] /media/migeul
sudo chmod 775 -R /media/migeul

This will create a group and attach it to the folder to be shared. You add the users to that group for access. Set the permissions to 775 which gives the owner and the group read-write-execute access while others only read. Set's it recursively.

Verify that you have total access to the folder. With samba, setting the permissions are a little bit different than file permissions with a ubuntu user. What I mean is that verify the permissions after you take ownership because they could result in a samba error later on down the road. Where nobody can access the drive.

Create a samba account that matches your Linux username precisely.

sudo smbpasswd -a miguel
sudo smbpasswd -e migeul

That will prompt you to create a password for the username miguel. Please note that this is only for SMB shares not for the user in the Operating System.

Afterward, open up the samba config and when sharing the drive make sure you type in writable = yes, browsable = yes, read only = no and add your group to it as well. Also, verify the location you are sharing from. Use the place that it is mounted to.

[migeul]
comment = Migeuls folder
​path = /media/migeul
​browsable = yes
​writable = yes
​guest ok = no
​read only = no
​valid users = @[samba_group]

After you reconfig the /etc/samba/smb.conf file, reload it.

sudo smbd reload

These pages go more in-depth with setting up samba shares.

https://help.ubuntu.com/community/Samba/SambaServerGuide https://www.techrepublic.com/article/how-to-set-up-samba-shares-for-groups/

You may also need to set your umask as well. To do that open up /etc/profile using sudo nano /etc/profile and at the bottom type in umask 002. Use Control+O to save and Control+X to exit. Best to reboot the server using sudo reboot and the new mask permissions will take place. That setting re-asserts the same permissions for the users.

Well, I didn't pose it in the form of a question, but the answer is there. Be sure to see that the user is listed as a Valid user in the smb.conf (located in /etc/samba/ on my linux machine).