my Mac is running OSX Yosemite 10.10.2.

I recently found out that in my console such messages:

[A process name and its pid]: The function ‘CGContextErase’ is obsolete and will be removed in an upcoming update. Unfortunately, this application, or a library it uses, is using this obsolete function, and is thereby contributing to an overall degradation of system performance.

would occur for every window I opened.

I tried $ sample -e -wait [Application Name] then launch the application, but in the report I can't find any call to CGContextErase.

Is there anyway to reveal what is behind all this?

Following is a screenshot of Console messages filtered with word CGContextErase:

a screenshot of console

Update 1:

I ran EtreCheck and here is the result.

I also discovered that such problem will not persist in a newly created account.

  • 1
    My guess would be that something that is being loaded into all these processes contains "CGContextErase". Possibly an outdated kernel extension, or something of that nature. I would suggest running EtreCheck on your Mac, posting the results to a Gist and updating your question with a link to the Gist. – Alistair McMillan Mar 23 '15 at 23:21
  • @AlistairMcMillan You mentioned a good point. I checked the kernel extension by running $ kextstat | grep -v "com.apple" and discovered no suspicious kexts. And I updated my question to include a report from EtreCheck. – toaruScar Mar 24 '15 at 15:20

I found the culprit. It was the outdated Tablet Driver from Wacom. After I uninstalled and upgraded it, there is no more such messages in console.


There are quite a few interesting things in that EtreCheck scan.

First of all Alipay appears to be crashing very regularly. If you don't use it I'd remove it completely. If you do use it, I'd remove it and reinstall it.

Given that the problem only appears within your own account I'd focus first on the items that are set to run within your own account rather than things that run under all accounts. One that stands out is AirServer. That could be something that is loading into the WindowServer and resulting in these CGContextErase messages across all applications. I'd recommend removing that and seeing if the messages cease.

If that doesn't resolve the problem I'd try removing other extensions, one or a few at a time, until you find the culprit. Starting with the ones you don't need or ones that hook into the system in a significant way (Default Folder X is another example). Given that you don't see the problem in another account, you could also try running EtreCheck under another account and comparing the two results.

Something else that might help locate the culprit is selecting one of the affected processes in Activity Monitor, then clicking on the Info button and selecting the "Open files and ports" tab. This should list everything loaded into that application and perhaps something will stand out.

Let us know how you get on.


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