I use a custom alpha for my signature on ZB work, so I like to have that alpha in my startup folder. Well, it wouldn’t load when I started ZBrush 4. Materials and textures load fine, other alphas load, just not this particular alpha.
I did find a solution, though, and thought I would share it before anyone else has a similar problem: From the alpha menu, I chose Import. Once the alpha was imported, I exported it back out, saving it in the ZStartup/Alphas folder. After that, it was there as it should be. I don’t know if it has to do with the bit depth (24 originally, 8 after Import/Export), but a 16 bit alpha that I had in there loaded without a problem. I used .psd files for this, by the way.