I recently installed Adobe Acrobat X Pro, which required the removal of my previous version (8 Pro). I have several PDF docs created in (8 pro) with signature fields. I reuse these docs inputting updated info. When I do I clear the signature field, and place a new signature. After installed (X Pro) I can no longer clear the signature fields to place an updated signature. I am assuming that the new installation deleted my old signature ID that I created with (8 pro). Is there any way to clear my old signatures?
I don't think it should have deleted the digital ID file, so if you can find it you should be able to add it in Acrobat. Seach you system for any .pfx files to see if you can find it. See this previous thread for some potentially helpful info: http://forums.adobe.com/thread/991314
In the future, be sure to keep a backup of any digital ID files you have.