Hallo TS,
noch etwas interessantes:
ntlm used to be the default which is why you never had to specify it discretely. Things have moved on however so the default is now ntlmssp. If you are accessing something which doesn't speak ntlmssp you have to override the new default with the old one.
Most NAS devices use older technology so they often require ntlm. If you access an OSX samba share however it requires ntlmssp so before you had to specify that in the mount options but now you don't.
There are winners and losers with every change.