If Snapz 2.5.x worked initially, but stopped working after doing a movie capture, the problem is most likely due to having third-party QuickTime components installed that are incompatible with your operating system. Previous versions of Snapz would attempt to load all of the installed QuickTime components when launched. If one of them failed, it may prevent Snapz from launching.
Since there is no way for us to validate third-party QuickTime components, Snapz will no longer load any third-party QuickTime components as of version 2.5.2. Please download and install the current version of Snapz Pro X to resolve the problem.