Adobe Acrobat uses a cache to save the names and locations of any PDF files that you open, enabling the program to add these files to its Recently Opened list. Although this service can be useful if you want to re-open a file quickly, it can also let other Acrobat users know what PDFs you have been working with. The Acrobat interface does not include a software option to clear this cached data. However, you can reset Acrobat's cache by adding a key to the Windows system registry.

Step 1

Open the Windows Start screen and type the word “notepad” (without quotes.) Click the “Notepad” icon to open the Notepad application.

Step 2

Enter the following code into the Notepad document: “Windows Registry Editor Version 5.00 [-HKEY_CURRENT_USER\Software\Adobe\Adobe Acrobat\10.0\AVGeneral\cRecentFiles] [-HKEY_CURRENT_USER\Software\Adobe\Acrobat Reader\10.0\AVGeneral\cRecentFiles]" (without quotes.)

Step 3

Click “File” and then “Save.” Enter a filename and location for the text file and then click the “Save” button to save the file.

Step 4

Close Notepad and return to the Start screen. Type “this pc” (without quotes) and then click on the “This PC” icon to open the File Explorer.

Step 5

Navigate to the location of the text file and double-click on it. The Windows Registry Editor will open a pop-up box asking you to confirm whether you want to change your system registry. Click “Yes” and then click “OK” on the following confirmation message to add the key to the registry and clear Acrobat's cache.