SupportAssist backup failed- no archive.z01 file

Hi

I created a backup with SupportAssist due to some issues with my network card that required resetting the whole laptop.  The backup was supposedly "successful" with no issues reported.  However, after resetting, when I went to recover files from the backup, supportassist indicated the backup was corrupt.  Upon further investigation, the final .zip file is empty, there is a BackupHistory.xml file with the full list of backed up files (and nothing shows as failed), and there are archive.z02 through archive.z31 files.  There is no archive.z01.  I really only need a couple files from this backup that were not available via other means.  Is there any way to recover?  I've tried opening with 7zip or winrar, but those didn't work, though it's very possible I was doing it incorrectly.  Is there some way to recombine the remaining 30 archive files into a single zip to recover?  or any other suggestions are appreciated.  thanks!