Qnap 501 and 502 Named Users Problem;
What is the Problem?
500 and 501 are Windows users on your network. (or used to be). I assume you created users for both yourself and your wife on the NAS with the identicalusername/password pair as your Windows machines. If you didn’t do this, then your Windows machines will only have “guest” access to your NAS, which you claim to have deliberately disabled.
How To Solve?
You should have a username/password on your Windows machine. (It most definitely should NOT be “admin”). You should create an identical username on your NAS with an identical password as your Windows machine.
You also need to put your NAS and your Windows machines in the same WORKGROUP.
Please refer to this Guide;