Q: Aperture won't open.

Why won't it open?

What exactly happens, when you try to open Aperture? Do you see an error message? How are you trying to launch Aperture? Click the Aperture icon in the Applications folder? Click an Aperture library?

Looks like the old Final Cut problem, do you have Final cut installed?

The easiest thing to do is reinstall the OS, sounds like a lot of work but an overlay of the OS is fairly fast and your user info will not be touched.

As always however whenever doing system work it is a good idea to have a backup of the system.

That is the same problem as here:

Dyld Error Message:

  Library not loaded: /Library/Frameworks/PluginManager.framework/Versions/B/PluginManager

  Referenced from: /Applications/Aperture.app/Contents/MacOS/Aperture

  Reason: image not found

There is a dynamic library missing from you system library.

The easiest way to fix this is by reinstalling MacOS X.  Boot into recovery and reinstall the system. You can install on top of your current system, see:  OS X: About OS X Recovery http://support.apple.com/kb/HT4718

This error is usually cause by an old installation of Final Cut. Did you recently install Final Cut?

See:  Aperture 3.x: Aperture unexpectedly quits if Final Cut Express 4 is installed http://support.apple.com/kb/TS3528

I sure hope, the recent Mac OS X update 10.9.3 did not bring this old error back.

Frank, did you see, that is the second case right after the 10.9.3 update:

Aperture wont launch

It will, and dont forget the backup.

Yes, saw it, chalk it up to coincidence for now. Don't believe 10.9.3 has anything to do with it.

You're welome, glad you got it fixed.