To use Try&Decide:
When the disk space in the location selected for storing virtual changes is minimal for applying the changes, the program asks you whether to apply or discard the changes. If you ignore the alert message, the program will automatically restart the system when the disk is full, and discard the changes.
If you have chosen Discard Changes and rebooted the computer with multiple operating systems installed, you won’t be able to boot other operating systems except the one used for working in the Try mode. A second reboot will recover the original MBR and make other operating systems bootable.