Ok, so have a Win10 share that I've been using for a long time. Currently on "Version 1607 (Anniversary Update)". It works fine from Kodi 17.6 on Win10 client, or Android and Android TV.
The fault messages I get in the log are "unix_err:'d' error : 'Permission denied'". Full log here: iVIj
Any ideas? It's a share without password, shared with "everyone"