This issue that I am bringing up has happened to me often when I reopen the zTool that I am working on, the changes that I made to the made was erased and was not saved when I have done that the last time I had Zbrush opened. In other words, heres the story, I was working on a model and before I exit out of zBrush I saved my zTool. Now, just today when I opened the zTool all of the recent changes I made to the model were not saved. I would like to know why this is happening because it does tend to happen to me often. If any body can tell me how to go solving this issue, I will greatly appreciated it.
ZBrush has a failsafe feature built into its save routines. Basically, it first writes the file to disk to check and make sure that the save was successful before it then copies that file to overwrite the old version. If the save fails, ZBrush will not overwrite the old version.
What you’re describing sounds like for some reason the save is failing.
One possibility is that your system is running low on resources or defragmented free space and so ZBrush can’t write the file successfully. This can happen if your disk hasn’t been defragmented in a long time. It can also happen if your model exceeds what your computer or ZBrush can actually handle. (For example, too many polygons or two many layers.)