Several people encounter problems with Adminer, that doesn't launch well, depending of the theme you use.
Problems reported with Adaptable, and i also have it with Essential and More (at least).
In Adminer plugin comments, Ruthine Burton wrote about this problem in november, and Christian Bocquet wrote about a solution in april :
to make this plugin compatible with the Adaptable or Essential theme, try to remove lines 56 and 57 from the templates/adminer.mustache file:
I think it's worth investigate. Thanks in advance.