Troubleshoot Safari plugins and extensions ...
From your Safari menu bar click Safari > Preferences then select the Security tab.
Deselect: Allow all other plug-ins. Quit and relaunch Safari to test.
If that made a difference, instructions for troubleshooting plugins here.
If it's not a plug-in issue, select the Extensions tab. If there are any extensions installed, turn that OFF, quit and relaunch Safari to test. If that made a difference, uninstall one at a time, quit and relaunch Safari to test.
Hold the shift key down and relaunch Safari.
Launch Safari. Click Safari in the menu bar.
From the drop down select "Reset Safari".
Uncheck the box next to " Remove saved names and passwords".
Safari > Preference > Advanced
Checkmark the box for "Show Develop menu in menu bar".
Develop menu will appear in the Safari menu bar.
Click Develop and select "Empty Caches" from the dropdown.
Turn off Extensions if any, and launch Safari.
Safari > Preferences > Extensions
Delete safari .plist file.
Quit all applications.
Option click the "Go" menu in the Finder menu bar.
Select "Library" from the drop down.
Library > Preferences > com.apple.Safari.plist
Right click it and select "Move To Trash".
Restart the computer/