Label split of ad' multiply defined

I’m receiving the following warning in Line 1: Label split of ad multiply defined.

I don't know what it means since in line 1 there is only \documentclass[a4paper,11pt]{article}

• Could you please provide an MWE (the smallest possible yet complete document that demonstrates the problem)? – Marijn Jun 27 '16 at 9:04
• it means that you have \label{split of ad} in two places. (the line 1 will refer to a file that is input, not your main file) – David Carlisle Jun 27 '16 at 9:19
• Thanks so much @DavidCarlisle that was precisely the problem! – inquisitor Jun 27 '16 at 9:32

It means that you have \label{split of ad}` in two places. (The line 1 will refer to a file that is input, not your main file.)