Problem

Error during AECOsim Building Designer shortcut execution: "runwait_mshta_en_productinstallerGUI.hta, Access is denied"

Solution

The .exe extension on a filename indicates an executable file. Executable files may, in some cases, harm your computer. Therefore, please read below to decide for yourself whether the mshta.exe on your computer is a Trojan that you should remove, or whether it is a file belonging to the Windows operating system or to a trusted application.
https://www.file.net/process/mshta/exe.html
Try to right click, "Run As Administrator" on the executable first and also check your operating system and internet explorer for updates.
If all else fails, try running a maleware program on your computer, such as Malewarebytes.