Windows prevents things that need admin permissions from running with normal startup methods ⸺ like adding a shortcut to an app to the startup folder within the Start menu. To force it to happen anyway, you'll instead need to load up the Task Scheduler and create a task that runs the desired app with the highest privileges available.
There are plenty of tutorials online for this process, so I'll only hit the bullet points:
- Find Task Manager in the Start menu and run it
- Or hit Win-R and type
taskschd.mscin the Run dialog
- Or hit Win-R and type
- Create a new task from the Action menu
- On the first tab, check "Run with highest privileges"
- Add a trigger for "At log on of any user"
- Add a "Start a program" action for your desired app
- Hit OK and you're done
Why would you need an app to run on startup with admin privileges? I'm sure there are plenty of reasons, but mine is to stop my PC from throttling the CPU. It seems the motherboard and/or CPU is faulty or misconfigured: a "BD PROCHOT" code is thrown from the moment the system is turned on regardless of the actual temperature of the CPU. Speeds tumble from 4.4 GHz to 800 MHz to "protect" the CPU from damage the system thinks is coming but isn't.
It's been this way since the moment I built this old PC however many years ago. Never in gaming with a temperature readout displayed have I seen the CPU reach even half the temperature required to throw a "BD PROCHOT" error ⸺ even as a simple air-cooled system. The "fix" (as opposed to an actual fix that may cost money) has been for me to launch the ThrottleStop app after logging into Windows.
Tired of being forced to take that step myself, I tried throwing it into my list of startup apps to no avail. I assumed this was a bug, never looked into it, and manually launched it as my first post-login task for years. I eventually got curious enough google it, and I had a facepalm moment when I saw the restrictions startup apps that require more than regular permissions.
Thanks to ThrottleStop and (eventually) the Task Manager, I can now lazily continue to ignore this issue my PC has always had. One day I'll build a new one and this will all be behind me.