You can set Safari to the default settings
Sometimes it is helpful to have the Browser completely reset. Note that you previously, your bookmarks, secure should. A guide for Yoemite you will find in the next paragraph. So if you want to Reset the browser in previous Mac OS versions.
- Click in the upper menu bar, click "Safari" > "reset Safari".
- Remove a checkmark if you want to keep a setting.
- Confirm with "Reset".
- Now you can use the bookmark import.
- Note: This section applies to Mac OS X 10.9.5 on a MacBook Air with Safari Version 7.1 or 8.0.3.

The default settings in Safari
Reset Safari on Mac OS Yosemite
Since Mac OS X Yosemite, there is no setting more, with the bundled remove several options. We will explain you how to reset yet step-by-step Safari to the default settings.
- You open the settings, touch on Safari and select "settings".
- If you delete your data in the tab "passwords" by clicking on "remove All".
- Reset under "privacy" settings with the Button "remove All Website data".
- Under "notifications," choose "remove All".
- Outside of the settings you can find in the menu item "history" you Option the "history and Website data delete". Select "entire history" and "clear history".

Yosemite: reset Safari
In the other articles, read, like in Safari for iOS 8, the Tracking disable , and in iOS 8, closed Safari Tabs to restore.