The override default behaviors module is a tricky one, sometimes it can not get installed correctly fort various reasons, mostly permission issues and conflicts with 3rd party modules you've installed. Your site can't work correctly if it's not installed & enabled.
How to manually installed the override default behaviors module in Transformer theme v4 and Panda theme v2.
- Go the BO > Modules page to check the Overriding default behaviors module.
- If it's installed but not enabled, then jump to step #2.
- If it's not installed, then install it, ignore errors, just need to make the module's status change to installed by not enabled.
- Backup these files first if they exist, and then remove them.
- Copy folders in the \modules\stoverride\override\ to the \override\ folder. If you don't know how to copy files, you can just download them from the \modules\stoverride\override\ folder, and then upload them back to the \override\ folder.
- Move to the next step if you didn't install any 3rd party modules. In this step, you need to compare files marked in Orange in step #2 with their backup files, if there are differences, then you need to merge those differences, that requires knowledge of PHP. You probably have already find that the \override\controllers\front\CategoryController.php file is a special one, it's not supposed to be in there, it should be in the \override\controllers\front\listing\ folder. if you have one, compare it with the \override\controllers\front\listing\CategoryController.php file.
- Rename the \modules\stoverride\override\ folder to override1.
- Go the BO > Modules page to enable the Overriding default behaviors module.
- Rename the \modules\stoverride\override1\ folder back to override.
- That's all, good luck.
If you need our help, create a topic on the support forum.