There are many possible causes for problems with web browsing. Below are some simple steps that may either solve the problem or point the way to a solution.
Back up all data before making any changes.
1. Restart your router and also your broadband device, if they're separate.
2. If you connect to the the router with Wi-Fi, turn Wi-Fi off and then back on.
3. If you connect with Wi-Fi and you can also connect with Ethernet, do that and turn off Wi-Fi.
4. If your browser is Safari, then take the steps recommended in this support article.
5. If the Downloads button (with the icon of a downward-pointing arrow) is showing in the toolbar, click it and then click Clear in the box that appears. The download history will be removed.
6. In the Security tab of the preferences window, uncheck the box marked
Warn when visiting a fraudulent website
if it's checked.
7. If you're running OS X 10.10 or later, select the Search tab. Uncheck the box marked
Enable Quick Website Search
if it's checked.
8. If you're running OS X 10.9 or later, select the Advanced tab and uncheck the box marked
Stop plug-ins to save power
Quit and relaunch the browser.
9. If you're running OS X 10.10 or later, open the General pane in System Preferences and uncheck the box marked
Allow Handoff between this Mac and your iCloud devices
if it's checked.
10. Enable guest logins* and log in as Guest. Don't use the Safari-only “Guest User” login created by “Find My Mac.”
While logged in as Guest, you won’t have access to any of your documents or settings. Applications will behave as if you were running them for the first time. Don’t be alarmed by this behavior; it’s normal. If you need any passwords or other personal data in order to complete the test, memorize, print, or write them down before you begin.
Test while logged in as Guest.
After testing, log out of the guest account and, in your own account, disable it if you wish. Any files you created in the guest account will be deleted automatically when you log out of it.
*Note: If you’ve activated “Find My Mac” or FileVault, then you can’t enable the Guest account. The “Guest User” login created by “Find My Mac” is not the same. Create a new account in which to test, and delete it, including its home folder, after testing.
11. Are any other web browsers installed, and are they the same? What about other Internet applications, such as iTunes and the App Store?
12. If other browsers and Internet applications are also affected, follow these instructions and test.
13. Open the iCloud preference pane and uncheck the boxes marked Safari and Photos, if they're checked.
14. Are there any other devices on the same network that can browse the Web, and if so, are they affected?
15. If you can, test Safari on another network.
16. If you know that you've modified the hosts file to block access to certain servers, undo that modification.
17. Start up in Recovery mode. In the OS X Utilities screen, select Get Help Online. A clean copy of Safari will launch. No plugins, such as Flash, will be available. While in Recovery, you'll have no access to your saved bookmarks or passwords, so make a note of those before you begin, if they're needed for the test.
After testing, restart as usual.
