OK will do
So I have now uninstalled PDF-XChange Editor and even removed all possible traces using Martau Total Uninstall in several different ways.
I still see delays of 3 to 5 seconds when opening certain folders. The delays also occur when opening the same folder again within, say, the same minute. After opening the same folder several times, the delay disappears for a while, but then comes back again.
I have opened a new thread here.
PS: Solved! Issue was was due to