I have made 3 Blender projects about my Boeing 474 and have use 5 textures from my Flight Texture file.
When I press Ctrl+W Save Over I got nasty messages: Report Error: Unable to pack file.
I deleted all materials and textures and start all over and rename my blend file with a brand new name.
I drag all my flight textures to texture file and then add them back again in to my new747 project.
Inside External Data I select the box Automatically Pack into .blend, then I press Ctrl+W Save Over but still have the same problem. I understand why. I have deleted all stuff from the old project and rename the new one.
Do you know whats the problem.
I run on iMac 10.9.4 Mid 2011 and Blender 2.7.0