Couln't find file "C:\Users\< folder username>\AppData\Roaming\OBS" but I did find something similar, but it ends with "obs-studio" instead of "OBS"maybe, it all depends on the previous version to the problem.
To avoid any problem, and if your profiles and scenes are not too complicated to redo, delete everything (check everything) in order to start on a clean installation.
Be careful, the problems can and especially come from plug-ins which have become obsolete (not up to date) since version 28. You must also manually clean the OBS installation folder and also delete the C:\Users\< folder username>\AppData\Roaming\OBS