Is the machine you are working with a shared one where you also have/had Acrobat Pro installed?
64-Bit Reader version will automatically update to Acrobat Pro if any user/staff member has a subscription.
If you have installed Acrobat Reader 64-bit and you purchase an Acrobat subscription, the Acrobat Reader 64-bit application will upgrade to become a fully functional Acrobat 64-bit application. To identify the installed application, do the following:
Quit Acrobat or Acrobat Reader application if it's already running.
In Start > Search, typeRegEditand pressEnter. The Registry Editor is displayed.
If the value of SCAPackageLevel is 1, the installed application is Acrobat Reader.
If the value of SCAPackageLevel is greater than 1, the installed application is Acrobat.
Browse to the following registry locationHKEY_LOCAL_MACHINE\SOFTWARE\Adobe\Adobe Acrobat\DC\Installer\,and check the value of the key SCAPackageLevel.