In the Manager.properties file (in /opt/Vontu/Protect/config), change the setting:
com.vontu.manager.maxshowallincidents=10000
Comments in that section indicate that memory errors might occur if this number is set too high.
If exporting a report with more than 10000 incidents via email, this setting may need to be changed in the sale file:
com.vontu.manager.maxautodistributionincidents=10000