Clear an attempt to split a file

I need to split/break-down a .pdf file into sizes smaller than 35mb. I tried but I have no idea what happened. Now when I try, even when deleting the original file I had attempted to split and renaming it, when I try to split it the option is "greyed" out. I am asking how do I clear memory of Acrobat so I can split a file as needed? As well, will the bookmarks and page numbers remain intact?