Fortunately I have a second PC to test installations. I downloaded the latest version of OBS for portable installation from “Download | OBS”
I selected “Download Zip” for “OBS-Studio-32.0.4-Windows-x64.zip” to a folder on Drive D “D:\PROGRAMS\OBS” and “extract all” to the same folder. I ended up with -
"D:\PROGRAMS\OBS
bin
data
obs-plugins
I then downloaded the OBS Spout plugin installer " OBS_Spout2_Plugin_Install_v1.9.0.exe " from “Releases · Off-World-Live/obs-spout2-plugin · GitHub” to a temporary folder.
I ran the installer (OBS was closed and not run yet) and kept the default destination “C:\ProgramData\obs-studio\plugins” . This completed OK.
I then ran OBS (obs64.exe) from the folder
“D:\PROGRAMS\OBS\bin\64bit”.
Under “Sources” click the “+” to add a source and I see “Spout2 capture” in the list of sources.
I add that and run the Spout demo sender. Get it from “Release Spout 2.007.017 · leadedge/Spout2 · GitHub” and it worked straight away.
Configure OBS Spout output with “Tools > Spout Output Settings”.