Well there is your problem. Norton (and all other third party AV apps) is 100% worthless and does absolutely nothing nothing that Mac OS does not already do. Please read macOS - Security - Apple to learn about that. If Mac OS is simply kept up-to-date and. you restart your Mac about 1x per week you will be rewarded with a fast, stable and a secure experience. What the list of apps I mentioned earlier do is the exact opposite of what users want. They make Mac OS:
- Slow
- Unstable
- Provide unpredictable behaviours
- Make Mac OS appear buggy
- Can damage Mac OS
- and do nothing to enhance the users experience
In short they are simply bad news!
Please locate Norton's uninstall instructions and please follow to the letter. Then restart your computer in Safe Mode and then restart normally and test. Then please let us know your results. If the problem persists please let us know and we can do more troubleshooting.