On a Mountain Lion (OS X 10.8) machine or Mavericks (10.9) machine, the USB version of SimUText may be reported as "damaged" if your USB stick (flash drive) is formatted for a Windows file system.
To run SimUText on newer Mac systems with the USB version, the USB device must be formatted for a file system other than FAT32, such as Mac-Journaled.
How to run the USB version of SimUText for Mac OS X on a flash drive
The file systems used on USB stick devices (also known as flash drives or thumb drives) can vary. In some cases, you may be able to use a USB stick formatted for Windows to store and run Mac programs, including SimUText for the OS X operating system.
However, SimBio has been able to confirm that on OS X 10.8 (Mountain Lion) and 10.9 (Mavericks) machines, if the USB stick is formatted with the FAT32 file system (a common choice for Windows USB storage devices), SimUText may not run properly or may not launch at all. Instead, after the downloadable disk image (.dmg file) is mounted and the SimUText program is installed on the USB device, the system will report "This application is damaged" when you try to run the program.
The simplest solution for this problem is to use a USB device in your Mac computer that is formatted with a native Mac OS file system. Alternatively, you may be able to add support for NTFS file systems (as a system preference or an add-on utility) to the Mac where you want to use the USB version of SimUText.
Note: This problem has been observed only since the release of the OS X 'Mountain Lion' operating system. On Lion (OS X 10.7) and earlier operating systems, SimUText on USB has been shown to run even if the USB device has the FAT32 file system formatting.