I’ve tried using the name of the category, it worked for one category but not another, so I’m not sure what the exact trick is.
Also, the FAQ states you must use the category name not ID.
One of my categories has a space in it’s name, perhaps that’s the problem.
See: http://www.eatsleeptinker.com
The “Garage Sale” category should be excluded.
This is a fix
on file collapscatlist.php on function collapscat_catfilter (line 366)
Replace the line 379
for ($i=0; $i<count($categories); $i++) {
by
for ($i=count($categories) -1 ; $i>=0 ; $i--) {
This page works sometimes but not in any case. I think the logic is wrong at this place.
I found this solution https://wordpress.org/support/topic/some-categories-will-not-exclude?replies=2
It is helpful if you want to use this plugin with exclude feature.