asking for serial number whenever I try to open a pdf document

[jackimoya]

All of a sudden, a Acrobat XI Standard window pops up whenever I try to open a pdf.  I put in the serial number and get another window that says Serial Number Upgrade saying the "Serial Number you provided is value, but a qualifying product could not be found on this computer.  To use this serial number, you must own one of these qualifying products.  Please choose one of these qualifying products.  Please shoose the one you own and enter its serial number".  None of the product options are for Adobe Acrobat XI Standard, which is the product I purchased/am trying to use.

[John T Smith]

https://accounts.adobe.com/ then click Plans & Products at the top to find all of your registered serial numbers

From what you say, you have an upgrade version and the program will not properly register until you enter the serial number of your previous version

[jackimoya]

I tried an earlier serial number (for Adobe Acrobat 10) and now the error message says "the serial number you entered is invalid.  Please try again with a valid serial number".  I've been using AA 11 for 3 years with no problem and just this afternoon, I can't do anything...

[Del Z]

Hi Jackimoya,

These help documents may provide a solution:

Invalid serial number error

Error: "The serial number is not valid for this product" | Adobe Creative Suite‌

I am also moving this discussion to the Installing, Updating, & Subscribing to Acrobat in case further troubleshooting is required.

Best,

Del