Use TweakUI To Set the Number Of Customized Folders In Explorer

Many users want photo folders to show up with thumbnails in Explorer and have, say, everything else default to the list-based detail view. But if you have a large number of folders, Windows won’t keep track of them all, and if you go over the default of 400, some will revert to the standard view. This can be tweaked in the registry but it’s easier with TweakUI: You can get Windows to remember up to a maximum of 65,527 customized folders with a simple change.

In TweakUI, scroll to Explorer > Customizations. Change the “Folders to remember” to whatever number you’d like.