On my Samsung Galaxy S7 some newly downloaded pdfs disappear. They aren't in the "Recent" or "Local" sections. However, when I click the file icon displayed in Recent section, the file names are there. When I select one a window pops up saying: "Opening file.... Adobe Acrobat will create a local copy of this document." I select continue and a dialog box opens and closes quickly but the pdf is not listed in Recent or Local.