Premiere Pro won't open as can't access Preferences folder

you might try creating a new user account with administrator status in system preferences:  users and accounts.  

certainly can't hurt to ask at the genius bar.  If by any chance, you're in NYC, you'd be welcome to stop by my edit room with your laptop...

If you hit the blue reply button at the top of the thread, you can actually embed the screengrab in the post.  People seem to get upset if you don't do that.  Me, not so much.  Try clicking on the plus button at the bottom of the info window and make sure your user name is added and if it doesn't have read/write permissions, try changing it...  My preferences folder has me at the top of the sharing and permissions list...

can you post a screen grab of the info window for the folder.    

I'm assuming you're on the mac.  Are you signed in as an administrator on the computer?  If not, find out who is and either get them to fix this, or give you administrator priveliges.  This is handled in the system preferences:  users and accounts.  Since I work on my own computer I really don't know exactly how the computer behaves if you do not have administerator priveliges.   

if you're on the mac you may not have "permissions" to access this folder.  If you can find the folder in the finder, right click (or control click) on the folder and choose get info.  You need to make sure you have permissions.  You have to unlock and then change the appropriate permissions for the folder and then click the gear wheel and apply to enclosed items.  If this isn't clear, post back.  I imagine that the same thing is true on a windoze machine, but haven't had to deal with one in a while 

Hold Alt (Windows) or Option (mac) while opening Premiere Pro. Does that help?

https://community.adobe.com/t5/Premiere-Pro/FAQ-How-to-reset-trash-preferences-in-Premiere-Pro/td-p/8236158