2.69 Cycles Texture Problems (purple!)

I’ve been having a real problem with textures in 2.69 Cycles on a Mac the last couple days. If I add an image texture node, it shows up exactly as expected. But, if I pack or unpack files, or I close Blender and then later re-load the file, the textures all show up as purple in renders and previews.

Re-assigning the texture or re-picking the same file from disk doesn’t fix it. Creating a new node sometimes fixes it, but not usually. Making a new copy of the texture on my hard drive with a different name and assigning that to the texture node fixes it… until the next time I open the file, or I pack/unpack images.

The images are definitely loading into Blender fine. . When I look at them in the UV/Image Editor, they are there. When I select them in the Image Texture node’s dropdown, the preview icon shows the correct value. They work in Blender Internal and in texture paint. But, in Cycles preview, or a Cycles render, I just getting purple everywhere except right after the first time I load a file from disk.

I’ve tried re-downloading and re-installing Blender 2.69, and I’ve tried moving to a different machine, and I’m still getting the same result.

If anyone has seen this and/or has any thoughts about what might be going on, I’d appreciate the feedback, but right now, my only option is to go back to 2.68 unless I can figure this out.