OpenMM does not give progress for minimization, just wait...
RNA-test_mdr.pdb ...
1 nm
Energy at Minima is -194414.222 kcal/mol
saved  RNA-test_mdr_min.pdb
Cmd: rna_minimize.py -sp RNA-test_mdr.pdb
Execution time: 257:07:11.893  start: 17:12:01 end: 10:19:13  
DONE!