Is there a way to increase the speed of calculation (by turning off virus scan)?
It could be that a virus scan highly decreases the speed of the program SCIA Engineer. An example of how this can be solved is given below for a Symantec protection.
You should not turn it off completely (which can be dangerous), but you can exclude programs for the scanning process.
Below are some screenshots given.
First you can configure the settings to exclude files, folders and processes
Here you can then add specific folders and subfolders of SCIA Engineer:
This could provide a solution to crashes and slow calculations.