How to Clear the History on an Adobe Reader
From removing outdated links to simple document management, there are many reasons for clearing the recent document history from within various applications. Numerous third-party software providers offer solutions for clearing this history, but users of Adobe Reader can perform the task for free from within the application. Accomplish the task of clearing the Adobe Reader recent document history with only a few clicks of the mouse.
Open Adobe Reader and click the "Edit" toolbar.
Select "Documents" from the panel located on the left of the screen.
Change the "Documents in Recently Used List" setting to 1.