I have an application that was upgraded successfully to PB 2019. Our application ran well with the PB 2019 run time files on users' computers. We upgraded to PB 2021 build 1311 successfully. I deployed 12 applications successfully and tested the exe's on my development computer without incident. I installed the PB 2021 runtime files and the application on a test computer and then ran the application. We have one main application that calls the other applications. The main application runs without incident but when it runs the other applications some appear briefly and then disappear. Others never appear. Any help would be appreciated.