Hi, welcome to justanswer.com! My name is Mike.
I can trouble shoot this for you by remote control if you wish.
I can't be sure until I run some tests
We do it all the time and you can check the credentials of this site. Also see my record here: askmikethemacmedic.com You can take it somewhere else if you wish. No problem.
I give you an app to install and it is safe and secure and I have no access after we are done. You are right to be wary but this site is safe.
OK good luck, I offered to help for $36 more for the record...
There are things you can try yourself but I thought you were in a hurry... remote help is the fastest way.
Reboot into the Recovery HD by choosing the ‘Apple‘ menu > Restart, then hold down the ‘Command’ + R’ keys on the keyboard during the start up process. If you can't get to that menu just hold the power button for 10 seconds until it shuts down. Then start it up again holding those keys. When you see the Apple Logo you can let go.
When the machine boots you may have to choose your language then you will see the OS X Utilities screen. Select the Disk Utility and then Continue. Then in Disk Utility select Macintosh HD in the left column (if there are two with that name or it is named something else choose the first indented item) and then on the right select the First Aid tab then select Run.
If all is OK I have some other tricks using the Terminal app.
The price is also negotiable.
Ok but you should learn how to do these things regardless they are normal maintenance and should be done even if the computer is new.