T.2.2.1 Is an error message displayed?

At startup of Editor

Cause

If any of the following error messages appears, two or more GP-Pro EXs or different versions of GP-Pro EX cannot be started.

Solution

The number of GP-Pro EXs that can run at the same time is two. Different versions of GP-Pro EX do not run at the same time. Start the same version of GP-Pro EX as the one currently running.

At startup of a project file

Cause

If an error message, as shown below, appears when opening a project file, the project file you tried to open may have been created using a later version of GP-Pro EX. A project file created by a later version of GP-Pro EX cannot open in a previous version of GP-Pro EX.

Solution

If you are using GP-Pro EX Ver 3.0 or above, please use the Version Reverter to lower the version of the project file, and open the file in GP-Pro EX.
3.7.2 Procedure - Converting the project file to a previous version using the Version Reverter

If you are using GP-Pro EX Ver. 3.0 or earlier, use the version of GP-Pro EX that you used to create the project file or a later version of GP-Pro EX to open the project file.