Hi kranthikumar,
Welcome to post your question in Microsoft Q&A!
Thanks for reporting this issue, currently this is a known issue in our internal system.
If you still want to delete folder using FolderPicker, the workaround is that first we need to get the parent folder of the selected folder, then pass the selected folder name to the parent folder to get the folder instance, after that we can delete this selected folder as following:
var folderPicker = new FolderPicker()
{
SuggestedStartLocation = PickerLocationId.DocumentsLibrary
};
folderPicker.FileTypeFilter.Add("*");
var folder = await folderPicker.PickSingleFolderAsync();
try
{
var parent = await folder.GetParentAsync();
var folderToDelete = await parent.GetFolderAsync(folder.Name);
await folderToDelete.DeleteAsync();
}
Thanks.