Muscore 3.5.0 no longer plays back. Option unavailable

Hi all,

I used 3.5 the morning of 2/13 - no problems. 2/14 the option was greyed out. I went through and reverted all settings, reverted the I/O, and followed all other steps on the list. Still does not work.

Running on a windows 10 Surface Pro. all the system req. met.

Thanks for the help!