Black squares in Safari

Test with another browser, such as Firefox or Chrome. If it doesn't manifest the problem, you may be triggering a known bug that affects some MacBook Pro models with dual graphics. The only workarounds I know of are to use another browser on the affected sites, or to disable automatic graphics switching if your model supports it. To use the discrete graphics processor, you'll need a third-party utility to switch to it manually.

From the Safari menu bar, select

Safari ▹ Preferences... ▹ Extensions

Turn all extensions OFF and test. If the problem is resolved, turn extensions back ON and then disable them one or a few at a time until you find the culprit.

Me too, you are not alone. It keeps obscuring things for me. I don't see it happening in Chrome or Firefox.

My only workaround is to "Select All" to try and see the text on the page again.

I thought it was just me, glad I found this, will be following along to see if there is a solution sometime. The quality of Mac software over the last 2 years has been appalling.

i have the problem with an old 2008 Mac Pro running Mavericks and Safari 7.1

frequently it decides to put the black squares on tabs. I found the "Select All" workaround also, but it keeps a black line somewhere.

the black square is not where the image is supposed to be, usually its on top of the page (not top-left, just top somewhere in the middle horizontally)

and it doesn't happen on all tabs (i have a few dozen open usually) and all windows (a dozen or so of these too)

page reload eliminates the problem also (until it happens again)

i would agree with sentiments about quality of software.

the mac pro 2008 never run as smooth and fast as with snow leopard. that was the best osx release ever.

I have the same problem. Just updated Safari to 8.0.4, and still have the problem. It doesn't appear all the time, and I can't find a pattern to when it does. Refreshing the page makes it go away on my mac.

I'm testing to disable Automatic Graphic Switching now (turned it off just now), but the problem also occurs when I have an external screen, and if I haven't missunderstood, the high-performance graphics is used for external screens.

"When your computer is connected to an external display, high-performance graphics will remain on until you disconnect the display."
Quote from MacBook Pro and MacBook Pro with Retina display computers: How to set graphics performance - Apple Support

My computer spec are: MacBook Pro (Retina, 15-inch, Early 2013), OS X Yosemite 10.10.2 (14C1510)

same problem. gonna apple fix this bug? are there any schedule?

Happens here too. 😟

Am on 10.3.3 Late 2011 MacBook Pro.

Seeing it here too:

2012 model retina MBP running OS X 10.10.3, graphics switching turned off. Big black squares which disappear when I refresh the window.

The same here - Mac mini (Mid 2011) running 10.10.3 and Safari 8.0.6

The same here. Mid 2014 macbook pro dual gnu running 10.10.3 and Safari 8.0.6

Same problem. iMac 21.5 Late 2009. OS X Yosemite 10.10.4

I have the same problem. 27" iMac Late 2009 (Core i7-860), OS X Yosemite 10.10.4

Same problem exactly. Mid 2009 Macbook Pro, 8 gb ram installed. May be happening when I have a lot of applications open but haven't specifically tracked that. See it in Safari and Firefox.