The Z01 file type is a zipped or compressed file; it is part of a group of files known as a spanned zip file. Spanning is used to break larger files into small pieces for saving on a disk or emailing. The Z01 file will have at least one other file in the group; each file in the group will end in Z01, Z02, Z03 and so on until the entire span is completed. There is a trial utility that is easy to use that will open Z0X files.
Download, install and run Back4WinXP (see Resources).
Navigate to the folder containing the Z01 file you wish to unzip, click on it to highlight it, and click the "Restore" button.
Click on the Z01 file to select it and click "Open."
Click on the box next to the file you wish to restore to select it.
Click the "Extract" button.
Choose where you would like to save the restored file and click "OK."
Click "OK" in the box indicating that your file has been successfully extracted, and close the program.
Since the Z01 type file is a multiple-part file, if you are missing one part of the file, you may not be able to open any of them, or you may only be able to recover part of your data.