I saw these three console entries today:

2015-02-10 17:31:05.596 pkd[451]: UNINSTALLED:com.apple.Preview.Markup com.apple.Preview.Markup(1.0) 0E04B4EC-64DB-4C7F-B79B-AD11187C18FF /Applications/Preview.app/Contents/PlugIns/Markup.appex

2015-02-10 17:31:05.600 pkd[451]: INSTALLED:com.apple.Preview.Markup com.apple.Preview.Markup(1.0) <__NSConcreteUUID 0x7fb3b8f4d030> 5DD65E58-F722-4DF9-9850-6098D7ADC739 /Applications/Preview.app/Contents/PlugIns/Markup.appex

2015-02-10 17:31:05.653 pkd[451]: PLUGIN REMOVAL:com.apple.Preview.Markup RESULT:3

I do not know what triggered that uninstall/install process.

I have seen that Markup.appex Preview plug-in in other two OS X Yosemite systems, but not in a stock OS X Mavericks system. The plug-in appears to be legitimate, apparently providing some Mail functionality.

But why would the pkg process remove and reinstall it today, with no warning or explanation (in the form of an entry in “Updates installed in the last 30 days” list in the App Store app?

The App Store app doesn’t show that anything got updated today.

Even though the Extensions preferences pane in System Preferences refers to extesions as “third-party” software, Google doesn’t provide me the possible developer for the Markup.appex extension.

I doubt that (if the plug-in is an Apple product), Apple would update it silently, unless this is a security problem being plugged.

I appreciate any insight into this by someone who is familiar with the plug-in or knows how third-party extensions are updated.

1 Answer 1


Markup.appex is a new extension that was added in Yosemite. It delivers the Markup feature shown on Apple's Yosemite page:

Mark up attachments right in Mail. It happens often. Someone sends you an attachment that requires quick feedback. It could be a form you need to fill out and sign or an image you need to comment on. Markup lets you respond quickly to these requests without opening the file in another app. Just click Reply and add your notations right in your response. Add shapes, text, and callouts to images by drawing on the Multi‑Touch trackpad. Fill out forms and PDFs, and add your signature by signing with your finger on the trackpad or capturing it with the camera on your Mac

Is it possible you installed the 10.10.2 update lately?

  • Well, yes. I installed the 10.10.2 update on 2015-01-28, almost two weeks ago. Given that pkd is managed by launchd, it appears that these extensions live in an update world different from other software. They seem to be updated silently. I will check the other three Yosemite systems under my control, to find out whether the Markup extensions are also updated silently. Feb 11, 2015 at 6:25
  • It's not clear to me that Markup.appex itself was actually changed -- pkd may have simply decided to refresh its info about Markup.appex (by deleting and recreating its info -- not the actual Markup.appex file). Feb 11, 2015 at 7:11
  • No. Markup.appex did not change, at least according diff. I am very curious about what could cause pkd to uninstall and reinstall an app extension. Does it do it at regular intervals? I will see what kind of documentation Apple has about spontaneous uninstall/install procedures on app extensions. The Markup extension is authored by Apple, by the way. Feb 11, 2015 at 7:22
  • No explanation about the spontaneous uninstall/install. Oh, well. Ignorance is bliss. Feb 11, 2015 at 7:29
  • I've got no idea what could have triggered it. Feb 11, 2015 at 15:29

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