Hi,
I haven't encountered this error, but looking at the KB you mentioned, it seems these non-ascii characters could be present in one or more files, which could be very laborious to check. I hope you have checked not just in the file names but also in the content inside those files ?
Check if the Data ONTAP 7-Mode system configuration contains extended ASCII characters, like the German umlaut. These characters might be present in usernames, CIFS share definitions, ACLs, usermaps, and domain names.
Look for such characters in:
Password files located at: /etc/passwd or /etc/group
From command line also you can remove them:
CIFS local users and groups configuration in 7-Mode
To remove Non-ASCII characters , use following commands :
filer> useradmin user modify
and/or
filer> useradmin group modify
Remove the extended ASCII characters and resume the transition by running the Apply Configuration command.
https://mysupport.netapp.com/NOW/cgi-bin/bol?Type=Detail&Display=811898
https://kb.netapp.com/app/answers/answer_view/a_id/1006292
Thanks!