I've had some issues in Pr with MXF.  This may or may not help.  Probably won't, but nobody else has offered anything so far.

I discovered that the files other than MXF in the camera card structure were causing problems.  I fixed it by separating the MXF from the other files, and then import the MXF into Pr.  Then they'd play and work fine.

Might be worth an experiment on your system.

On Mar 25, 2014, at 12:28 PM, Bruce Lambert <bruce.e.lambert@gmail.com> wrote:

Had a machine working perfectly fine importing Sony and Canon mxf files into projects running both Adobe After Effects CS6 11.0.4  and Creative Cloud 12.2.1 on Mac System 10.8.4.  Upgraded to Mavericks 10.9.2 and now I get error messages that the files are corrupt or unreadable from After Effects.  Nothing changed except the operating system.  

 

If I take those same files that my Mavericks system says is corrupt and import them onto another one of my machines running 10.8.4 they import into After Effects just as before. 

Just a note:  My mxf files from our Panasonic 370 import just fine using either system.  Anyone have any ideas or experienced this?