Cannot access Facebook via Mountain Lion

Just disable all the extensions in Safari first.

Then, if you can get to Facebook, renable them one by one and test after each till you can't get to Fb anymore. Then you know the culprit.

If after disabling all the extensions Fb is still unavailable, go to

/Library/Internet Plug-ins

and move everything out of that folder to a Temp folder on your desktop.

Restart Safari and see if the problem's solved. If yes, move those items back in one at a time and test after each till the problem recurs.

🙂

If you have the same problem in all browsers, then obviously it has nothing to do with Safari extensions, which can only affect Safari.

Launch the Network Utility application in any of the following ways:

☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)

☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.

☞ Open LaunchPad. Click Utilities, then Network Utility in the icon grid.

Step 1

Select the Lookup tab and enter

www.facebook.com

in the address field. Press return. Post the output – the text, please, not a screenshot.

Step 2

Select the Ping tab and do the same.

The DNS server that your router is using is sending back stale data, or the router itself is caching that data. Open the administration page of the router and look for its DNS settings. You should see one or more numerical addresses of the form "1.2.3.4". What are they?

If you want to post screenshots, please do so inline by clicking the camera icon in the toolbar of an editing window.

Then it's a problem with your ISP's servers. You can bypass them by entering the public DNS servers of your choice, either in the router (in which case all devices on the network will use them) or in the Network preference pane (in which case only that Mac will use them.) For example, you could use Level 3 DNS:

4.2.2.1

4.2.2.2

That's an example, not an endorsement. There's a slight chance your ISP might block those servers, in which case you'll have to use something else.

Triple-click the line below to select it:

/etc/hosts

Right-click or control-click the highlighted line and select Services ▹ Open from the contextual menu. You may be prompted to confirm. A TextEdit window should then open. Please post the contents of the window -- the text, please, not a screenshot.

The hosts file has been modified.

By far the easiest way to fix the hosts file is to restore it from a Time Machine (or other) backup that predates the modification. If that's not possible, then do as below. Please read this whole message before doing anything.

Back up all data.

These instructions must be carried out in an administrator account, if you have more than one user account.

Launch the Terminal application in any of the following ways:

☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)

☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.

☞ Open LaunchPad. Click Utilities, then Terminal in the icon grid.

Copy or drag — do not type — the line of text below into the Terminal window, then press return:

sed '/lo0/q' !$ > Desktop/hosts

You should now have a file named "hosts" on your Desktop.

Next, enter one more command, again without typing:

sudo sh -c 'cat Desktop/hosts > /etc/hosts'

This time, you'll be prompted for your login password, which won't be displayed when you type it. You may get a one-time warning not to screw up. Confirm. Quit Terminal.

Do not type anything in the Terminal window except your password.

That will fix the hosts file. You can now delete the file that was created on your Desktop.