Uninstall and reinstall After Effects.
i thought of this, but i thought there would be another way. cuz i have lots of important plugins
I just built a completely new machine. I didn't think it took very long to download and install all of my plugins, scripts, etc. Since you're not even starting from scratch, many of them can just be moved to a temporary folder before you uninstall. Alternatively, install a different version of AE and copy the plugin file from one to the other. Remember, your Creative Cloud subscription gives you access to all previous versions from CS6 onward to the present.