Apps don't run.

Boot into Safe Mode and try again.

If you've installed anti-malware, anti-virus, add-on filters, cleaning apps or such, remove all that per the vendors' instructions, reboot, and try again. That'll probably have to happen in Safe Mode, here.

Failing that, download and invoke EtreCheck while in Safe Mode, and open a reply here and then press the button that looks like a printed page, and that'll open a text input box within the reply that's usually large enough to paste the entire EtreCheck hardware and software configuration report.

Have you restarted the computer? Tried logging out of your user account and back in?

Try setting up another admin user account in System Preferences/Users & Groups to see if the same problem continues.

Isolating an issue by using another user account 

You also post an Etrecheck report run while you are booted normally.  If the log won’t post, try posting it in Pastebin and provide a link in a reply. After pasting the report in a PasteBin page, go to the top of the page, and copy the address in the URL bar. Paste that in a new reply.        Pastebin