Logic Pro X Logic Pro X 10.3 AU validation with splash screen

Hi Guys, I'm assuming that a preference file has become corrupted, as, each time I boot Logic, I am forced to validate each plug-in. As you can imagine, it's driving me nuts! Would one of you wizards direct me to which preference files need deleting? I'm running ProX 10.3 with Mac OSX El Capitan 10.11.8. Many thanks.