My Mac Pro (2013) freezes up in Safari

If Safari is slow, stops responding, quits unexpectedly, or has other issues - Apple Support

Note the time of the next freze. After rebooting open the Console app in Finder>Applications>Utilities and look for log entries at the time of the freeze. Post suspicious ones here.

Look before the log entry that starts with BOOT_TIME since that is the first line of a bootup

same issue but it started after update 10.11.4

check this forum: http://forums.macrumors.com/threads/macbook-pro-2015-with-osx-el-capitan-10-11-4 -system-wide-safari-freeze.1963711/

Safari/Preferences/Advanced - enable the Develop menu, then go there and Empty Caches. Quit/reopen Safari and test. Then try Safari/History/Show History and delete all history items. Quit/reopen Safari and test. You can also try try Safari/Clear History…. The down side is it clears all cookies.Doing this may cause some sites to no longer recognize your computer as one that has visited the web site. Go to Finder and select your user/home folder. With that Finder window as the front window, either select Finder/View/Show View options or go command - J. When the View options opens, check ’Show Library Folder’. That should make your user library folder visible in your user/home folder. Select Library./Caches/com.apple.Safari/Caches.db and move it to the trash.

Go to Safari Preferences/Extensions and turn all extensions off. Test. If okay, turn the extensions on one by one until you figure out what extension is causing the problem.

Safari Corruption See post by Linc Davis

Not sure whether, under El Capitan, the same tab options and choices exist as in Mavericks or Yosemite, but try this (especially on the iMac):

Open Safari sufficient to get the normal Safari menu at the extreme top of screen. For that, you don't necessarily need to be displaying a webpage. Then click Safari Preferences > Advanced tab. Change the browser fontsize to 14 or less. ("Never use font sizes smaller than ..."). Quit Safari and then re-launch it. This, for an iMac, usually sorts out the freezing of Safari. It's not a full solution but has proved to be an effective workaround for quite a number of users. Can't guarantee it'll work in your case but is worth a try.

Of course, ensure that Javascript is enabled (Safari Preferences > Security tab > Web content: enable Javascript). BTW, at present does Safari only freeze at specific websites?

It goes without saying that if you're using any anti-malware on either of your Macs, or any Extensions, they may well be interfering with the proper operation of Safari. If that's the case then remove them before applying the fontsize workaround.

Hello,

I just want add that I had also experienced this exact same "Freezing" problem.

The root of my problem seemed to be caused by safari extensions which were not properly deleted/uninstalled through the safari preferences dialogue.

I had to manually go into ~/Library/Safari/Extensions and delete several rougue extensions.

Since deleting I have not expereinced a "Freeze".....