Fn key can not work when logged in as a specific user

Question

I use fn + (F1-F12) to control my MBP(adjust brightness etc). This setting works well for more than a year.
Recently, when I logged into my user account, I found I can not use fn+(F1-F12) to adjust setting anymore. When I press fn + f1, the result is equivalent to just press f1 without holding the fn key.
The fn key can work well when I am in the login screen, but after I type my password and press enter, the fn key will not function anymore. Even logout can not help.
If I log into another user (guest or newly created user), the fn key can work well. If I log into my account first, then another user, the fn key will be disabled until I reboot my machine.
It seems that my user account launched some weird applications that disabled my fn key.
I tried to disable as many login items as I can, but the problem still remains.

Answer 1

Thank you for your answer.
Unfortunately I can't try your solution on the computer where the problem occurred because it is used in another course for the moment and is therefore not available. But I tried to recreate the problem on another computer. I created a restricted account and when logged in on that account I opened my VI and it worked fine... (all subVI:s were found). By default, the restricted account had Read & Execute, List Folder Contents and Read permissions for the MAX folder. So, I then unchecked the Allow-boxes in an attempt to recreate the problem, but the VI still worked on the restricted account. Then I checked the Deny-boxes for the permissions mentioned above, but the VI still worked. Since I couldn't recreate the problem I don't know if your solution is the right one, but at least I can draw the conclusion that it is possible to run my VI from a restricted account.
But I will try your solution on the computer where the problem occurred when it is available and I will let you know whether the problem was solved or not.