System Time Changing
here is the response I got that works for my situation: (Guest os different timezone than Mac-Host OS)
You can disable TimeSync completely by following these steps:
1. Locate the .pvm bundle of the virtual machine, by default it should be located in your Documents/Parallels folder,
2. Shutdown all virtual machines and quit Parallels Desktop,
3. Control-click the .pvm bundle, click 'Show package contents',
4. Locate the file config.pvs,
5. Control-click it, from 'Open With', select TextEdit, or text editor of your choice,
6. Locate the
<TimeSync
string,
7. Change "1" to "0" in <Enabled>1</Enabled>
8. Save the config.pvs file, and close it,
9. Start the virtual machine and check the issue.
It will disable timesync completely. To enable it, you may change this value back to 1.