Samba “Strict locking” prevented file to be modified
From certain number of linux SAMBA and higher, “strict locking =1” is the default. When such SAMBA share is mapped on older versions of windows, the files would be not able to be modified – you can create new file, modify it. However, when you try to save, it will return “The process cannot access the file because another process has locked a portion of the file”. However, you can still save the file under a different name.
To workaround this, you can add
strict locking = 0
in your smb.conf under [global], and restart the smb server. Everything will work again.