Photoshop CS6 Extended not taking Serial number

When you ask a question you need to provide some basic information

-Forum quick start https://forums.adobe.com/docs/DOC-5601

Mac or Windows, and EXACTLY which version of the operating system?

Recent Mac AND Windows operating systems have been known to cause "odd" problems

Are you using a computer Administrator account with full read/write permission?

What is the exact error message that you see?

CS6 is 4+ years old and no longer supported... some ideas for your (unknown) computer

CS6 and earlier programs have not been tested and will not be updated for Mac El Capitan/Sierra

-which means that you try to use CS6 and earlier at YOUR risk of having problems due to Apple updates

-Adobe has a fix to Apple's problem of not maintaining backward compatibility in El Capitan/Sierra

--several help links inside this message https://forums.adobe.com/thread/2301916

-also install OLD Java runtime if needed https://support.apple.com/kb/dl1572?locale=en_US

An idea that MAY work to install and/or run old programs in Windows 10... works for some, not for others

-RIGHT click the program icon or EXE and select a compatibility mode in the pop up option window

-or Run as Administrator http://forums.adobe.com/thread/969395 to assign FULL Windows permissions may help... says Encore, but sometimes required for ALL Adobe programs (this is NOT the same as using an Administrator account)

-or more on permissions https://forums.adobe.com/thread/2293598

NOTE - Win10 anniversary update version 1607 has caused MAJOR problems with old programs, so the above may not work

-Notice http://www.computerworld.com/article/3157369/windows-pcs/new-windows-10-build-is-a-monster-update.html