It seems like this issue caused by autofriend plugin, I've temporary comment out these following code from this file JoomlaFolder/plugins/user/autofriend/autofriend.php , because we no longer use this exists method in 2.1, can you update this to autofriend developer regarding this?

				// Check if Foundry exists

				//if( !Foundry::exists() )

				//{

				//	Foundry::language()->loadSite();

				//	echo JText::_( 'COM_EASYSOCIAL_FOUNDRY_DEPENDENCY_MISSING' );

				//	return;

				//}

By the way, can you try again and see whether all work fine now?

By the way, I already reported this to our developer, we decided to add it back this exists method in Easysocial 2.1.3 .

Once you update to Easysocial 2.1.3, you can uncomment those code as what i mentioned in earlier or reinstall again with this user friend plugin on your site.

just an update, I already reverted back this changes as what i made in earlier JoomlaFolder/plugins/user/autofriend/autofriend.php

Then applied some fix into this file -> JoomlaFolder/administrator/components/com_easysocial/includes/easysocial.php

Can you give it a check when you have free time? because it should work fine now.

Thanks Arlex
Autofriend is a Nordograph plugin and on their website they stated that all their stuff is compliant with ES 2.1, so i didn't test that.
But very glad its been sorted.

All is working fine again.
Thank you!

Will this change be incorporated into future releases (so I don't have to worry about re-applying the change if I update)?

Yes, we will included this fix in next release version as well.