OK. when I first start painting a texture on my models, I am able to undo those paint strokes, but somewhere between saving and dividing, my undo button won’t work for my paint strokes. I can undo zadd, and subtract and I can undo masking I do but not paint. The other weird thing is that if I fill the screen with my texture unwrapped it will undo my paint strokes. Has anyone else run into this bug and if so what can I do about it? oh and I’m running 1.23 on windows 98. 
I’ve had the same thing happen myself. After what you’ve painted on a model is converted into a texture, I haven’t been able to undo any additional strokes as well.
A possible solution to your problem would be to use the TextureMasture Script that can be found here:
http://pixologic.com/index.cgi?zscripts
I notice you mentioned that you have version 1.23. You’ll need version 1.23b to run TextureMaster. You can go to www.pixologic.com for information on how to upgrade.
you have TWO sets of (undo)
1:under Document
2:under Tools
one for 3d object edit mode(undo)
the other for like brushes(undo)
it might not be high lited to click it making it look like its not working because your looking at the wrong (undo)
and you may have ran out of UNDO
go to “Prefrences” and set your “undo” to the fullest maxmium
Thanks guys, I’ll have to check.
Neither form of Undo will work once the color is visible on the current texture in the Texture palette. That applies regardless of whether TextureMaster was used or not. However, TextureMaster is a huge help in that until you Pick the object back up from the canvas you can undo as many painting actions as your Preferences setting will allow.
Incidentally, if you want to change how far back you can Undo to, you can do so at any time in the Preferences palette. The new setting won’t be retroactive, though – ZBrush doesn’t track history past your current undo max. It will also use a bit more RAM to keep track of the additional history.
Anyway, the bottom line is that once your texturing has become visible in the Texture palette, no undo will work. It’s stuck. So you may find that it’s wise to fairly regularly duplicate the current texture so that you have something to go back to if you make a mistake. You can do so in the Texture palette by clicking the Texture:Inventory:Clone button.
There is also a handy button in the TextureMaster labeled as ATC. That stands for Auto Texture Clone. It’s default setting is off, so you will have to turn it on manually if you wish to use it. What the feature does is automatically clone the current texture immediately before modifying it so that you always have a backup. The reason that it’s turned off by default is that the more textures you have in your palette, the more memory that it takes. And of course, depending on your work style, you could quickly find yourself faced with about 50 textures that are only marginally different from one another. 
But used wisely, it’s a very nice feature.
Hope all of that helps!
Thanks for explaining, Aurick. You explained it much better than I did.
oh your painting in (edit mode)
sorry wont work with a "Texture 3d object.
but if you just paint it then it will work and if you want to undo your paint stroke you need to be out of edit mode if the 3d object is textured.
add texture pick a Brush that will work…
i miss understood you when you said painting a texture on my models i persume you was out of edit mode because you can only Paint texture with a brush and meaning that you Clicked a Brush and that take you out of edit mode…
Thanks for all the info, it will definetly help in the future. Just making sure I got this right though, once the painting is shown in the texture pallette there is no way of going back at all?
use the 3D Copyer to add your texture and you will beable to undo your paint stroke’s
That pretty much sums it up, Hotlicks. You can’t undo paint that’s been added to a texture. But you can back the texture up so that you can revert to it if something goes wrong.