studio not loading (after upgrade)

After upgrade to 7.10.9 studio no longer appears.

JS Console: 500 (Internal Server Error)

no errors in PHP / apache logs.

suitecrm.log shows these two lines:

Fri Oct 12 18:44:11 2018 [17440][7098c295-4ea7-26fe-af1d-4dda14b75350][WARN] CSS File Dawn/yui.css not found
Fri Oct 12 18:44:11 2018 [17440][7098c295-4ea7-26fe-af1d-4dda14b75350][DEPRECATED] PHP4 Style Constructors are deprecated and will be remove in 8.0, please update your code

Any ideas?

if I rename the custom folder it loads fine… Any suggestions on where to look next are appreciated.

Another custom module I apparently once tested out and it didn’t bring out all the trash… In my case this bugger: