It is possible to change the location where ZBrush will write temporary files when compacting memory. When working with ZBrush, it is often necessary for the operating system to manage very large amounts of data with frequent read and write access. (Approximately 4-8 GB of data.) If your system drive isn’t the fastest on your computer, you can set ZBrush to use a different drive instead. This is done by editing the ZBrushScratchDiskPath.txt file. On Windows this file is located in the C:\Users\Public\Public Documents\ZBrushData folder or C:\Users\Public\Documents\ZBrushData folder. On Mac OSX it is located in the Users/Shared/ZBrushData folder.