Questions on Prior Releases -- ExtendSim 9 & Older

All ExtendSim versions are upwardly compatible. So ExtendSim 10 will read in models built in ExtendSim 9, 8, and 7. ExtendSim 9 will read in models built in ExtendSim 8, 7, and Extend 6. And so on.

However, ExtendSim is not backwardly compatible. Models and blocks you build in ExtendSim 10 cannot be read by earlier versions, such as ExtendSim 9 or ExtendSim 8. Models and blocks you build in ExtendSim 9 cannot be read by earlier versions, such as ExtendSim 8 or ExtendSim 7.

If your operating system has recently been updated and you are using an ExtendSim release prior to 9.3, Windows may be blocking the launch. With release 1709 (October 2017) Windows changed how the memory manager worked, which caused crashing and hang ups when launching older installations of ExtendSim.

If you are using ExtendSim 9 (released prior to November 16, 2017), 8, or 7, get your fix here.


If you have a Network license and ExtendSim on Client devices no longer launches, the Service (exService) may not be running correctly. In cases where the Server has been restarted, exService sometimes fails to correctly re-communicate with Client devices. The solution is to Stop the Service on the Server, then Start the Service. (Note: A Client license of ExtendSim will remain launchable for several hours after losing communication with the Server’s License Manager. However, if communication is not restored, ExtendSim will not launch. Thus, this issue can occur many hours after the Server has been restarted.)


If you are trying to enter numbers into editable text boxes in a block dialog and nothing appears, the problem could be that your system has been set to use right-to-left text for programs that do not use Unicode. This setting will work for programs that are built to expect to use right-to-left text, but not for programs that are not set to expect this.

You may need to change your system locale. The system locale determines the default character set (letters, symbols, and numbers) and font that you use to enter information and that are used to display information in programs that do not use Unicode. Selecting a different language for the system locale will not affect the language in menus and dialog boxes for Windows or other programs that do use Unicode. Try changing the default locale to English (United States) and check to see if this helps.

To change the system locale, follow the instructions at:

If you receive an error message on your client installation when trying to check a license out of your ExtendSim 9 network license it is probably the result of not having sufficient permissions on your client machine to checkout the license. The checkout process requires some administrative rights on the client machine and many companies are restricting these rights from users.

Try using the right-click command Run as administrator. If this doesn't work, then you may not have been granted sufficient permissions by your company on the machine to check out a license.

exServiceCheck if exService is running as a Service. For Windows, look in Computer Management\Services and Applications\Services.

Task ManagerLook in the Task Manager's Details tab. Both exServer and exService should be listed as running and both should list the System as the User Name. If the User Name for either of them is not System, the License Manager needs to be reinstalled.

When you open and convert a model that was built in ExtendSim 9, the converted ExtendSim 10 model is not associated with a file association until it is saved. Data Import Export blocks use the model path name to resolve the relative file path name specifications. Consequently, Data Import Export blocks using relative file path names will not function properly until the ExtendSim 10 model has been saved and is associated with its file.

Make sure that you SAVE the new ExtendSim 10 model following its conversion from ExtendSim 9 before running it.

While trying to update your ExtendSim 9 license to the current release, you see "This copy of ExtendSim is incomplete. Please reinstall ExtendSim from your CD.”

An Updater is not a full installer. This message only appears for one of two reasons:

If you installed the 9.x updater but you did not install it to the same place where ExtendSim 9 is installed.

If you installed the 9.x updater on a machine that does not already have ExtendSim 9.

First check your computer (Program Files (x86) and Documents) to determine the location of the current installation of ExtendSim 9. If it is present, install the 9.x updater into those same locations so that it will replace the ExtendSim 9 files. If ExtendSim 9 is not present, you need to install ExtendSim 9 before installing the 9.x updater.

ExtendSim 10 was released in October 2018. ExtendSim 9.3.1, released October 2019, was the final update for the ExtendSim 9 series.

If you still need to use ExtendSim 9 (for example, the third party module you are using with ExtendSim has not yet been updated to ExtendSim 10), please know it will no longer be supported with updates. Hence, if Microsoft makes a change to their operating system, it may cause older releases of ExtendSim to stop working. Therefore, as is true for all software, we highly recommend using the most current release of ExtendSim.

If ExtendSim 9 is required, Single User ExtendSim 9 licenses are currently still available through these unique links, but may not be for much longer:

ExtendSim 9 Package   Cost
ExtendSim Suite 9 . . . $4995
ExtendSim AT 9 . . . $2495
ExtendSim CP 9 . . . $995
ExtendSim Analysis RunTime 9 . . . $495
ExtendSim Student 9 . . . $100
ExtendSim Demo 9 . . . no charge

Maintenance & Support Plans (MSP) cannot be purchased for retired software. In the absence of a current MSP, support is not provided and upgrades to ExtendSim 10 must be purchased at the full upgrade price. Even with a current MSP, technical support for ExtendSim 9 is minimal.

If you have a current Maintenance & Support Plan for a Single-User license of ExtendSim 9, we only provide support for transitioning from ExtendSim 9 to 10.

For Network licenses of ExtendSim 9, we can still provide new site.tmp files, upgrades to ExtendSim 10, and so forth, as long as the MSP is current.

ExtendSim 9 was released July 17, 2013. The ExtendSim 9 series reached its End of Life (EOL) on October 28, 2019 with the release of 9.3.1. There will not be any further ExtendSim 9 updates or security patches.

ExtendSim 10 was released October 2018. Until ExtendSim 11 is released and if the Maintenance & Support Plan for your ExtendSim license is current, we will continue to provide support for transitioning from ExtendSim 9 to ExtendSim 10.