iphone sync error : iTunes could not sync information to the iPhone "iPhone" because another sync client is already running

I have been syncing my iPhone with iTunes in my MacbookPro for last 10 years. Since yesterday, I am unable to sync my iPhone with iTunes. I ge the following error message everything I click on sync: iTunes could not sync information to the iPhone "iPhone" because another sync client is already running".

I have restarted my phone, reset it, restarted my laptop however I still keep getting this message. I suspect I inadvertently deleted some system files while deleting cache files. Please help me reset my iOS in my laptop to remove this problem. Thanks