App Store won't open
On Imac running High Sierra 10.13.6, the App Store won't open. I believe it was after a security update.
iMac, macOS 10.13
To find out if it's system wide or user specific, try this...
Open System Preferences>Users & Groups, unlock the lock, click on the little plus icon, make a new admin account, log out & into the new account.
Does it work in the new account?