We have a steady stream of reports of Rhino V4 crashing on Acer computers with eDataSecurity installed and other computers with Egis PSD securty software installed. The crashes happen whenever Rhino V4 attempts to display the file Open/Save dialog. We have determined that the crash is caused by a conflict between a program that is part of the Acer / Egis eDataSecurity tool and a Microsoft operating system component that Rhino uses. Acer / Egis is aware of the problem and there may be an eDataSecurity update that fixes the bug, but we cannot verify that this update works with Rhino. See http://www.igrouptec.com/oem-acer001/program-update.html for more details.