Microsoft Mouse and Keyboard Center doesn't recognize Sculpt Comfort Keyboard (Windows 8.1 x64)

There is no version 2.3.145 available for download from the official Microsoft hardware support website that I could find anywhere there.  The latest version available is 2.2.173.0.  You may well have installed hidden malware--and as yet unidentifiable because too new for current detection signatures--on your PC from the file download site where you obtained the unofficial driver.  Hopefully not but that is the chance you take when installing unofficial drivers and software from third-party sites.

I am Brazilian. And I downloaded from the Microsoft pt-br site the 2.3 version, you can check by your own here http://www.microsoft.com/hardware/pt-br/p/sculpt-comfort-keyboard/V4S-00005#support

You might not speak Portuguese, but you can understand this at the 'Suporte' section and then 'Softwares e Drivers'. 

I took a look at the English site too and I noticed that YOUR latest version is the 2.2

What is happening here?

What is happening? That is a very good question.  I do not know.  That is interesting, though, that the other-language support site got newer drivers and software first.  Hopefully the English sites will see the same soon.

Very interesting indeed. I don't know when they lauched this 2.3 version for us, but the changelog must be minimal, it might be changed only the language support even. 

The 2.2 and 2.3 version can be almost the same one who knows... 

But I can tell you that even in our 2.3 version the keyboard are not detected, which is funny in some point.

Microsoft has updated hardware components.  They are not under obligation to support older hardware constructs when newer is available or when they discontinue an older version or other hardware series.  They aim for backward compatibility but this is not always possible.

For those with older hardware (yes, even the retail and online stores still sometimes sell outdates hardware) they are recommending uninstalling mouse and keyboard center and using the IntelliPoint Software instead.

I agree with you but both the Sculpt Comfort Mouse, Keyboard and Desktop are not old hardware, they are some of the most recent. 

IntelliPoint is the old software used for Microsoft mice and keyboard, right? Which does not work with the newest hardware.

There is no version 2.3.145 available for download from the official Microsoft hardware support website that I could find anywhere there.  The latest version available is 2.2.173.0.  You may well have installed hidden malware--and as yet unidentifiable because too new for current detection signatures--on your PC from the file download site where you obtained the unofficial driver.  Hopefully not but that is the chance you take when installing unofficial drivers and software from third-party sites.

I am Brazilian. And I downloaded from the Microsoft pt-br site the 2.3 version, you can check by your own here http://www.microsoft.com/hardware/pt-br/p/sculpt-comfort-keyboard/V4S-00005#support

You might not speak Portuguese, but you can understand this at the 'Suporte' section and then 'Softwares e Drivers'. 

I took a look at the English site too and I noticed that YOUR latest version is the 2.2

What is happening here?

What is happening? That is a very good question.  I do not know.  That is interesting, though, that the other-language support site got newer drivers and software first.  Hopefully the English sites will see the same soon.

There is no version 2.3.145 available for download from the official Microsoft hardware support website that I could find anywhere there.  The latest version available is 2.2.173.0.  You may well have installed hidden malware--and as yet unidentifiable because too new for current detection signatures--on your PC from the file download site where you obtained the unofficial driver.  Hopefully not but that is the chance you take when installing unofficial drivers and software from third-party sites.

I am Brazilian. And I downloaded from the Microsoft pt-br site the 2.3 version, you can check by your own here http://www.microsoft.com/hardware/pt-br/p/sculpt-comfort-keyboard/V4S-00005#support

You might not speak Portuguese, but you can understand this at the 'Suporte' section and then 'Softwares e Drivers'. 

I took a look at the English site too and I noticed that YOUR latest version is the 2.2

What is happening here?

...

In other words, it fails to recognize Sculpt Comfort Keyboard when it's alone, and recognizes it just in pair with mouse.

The problem now is that I don't know what to do with single keyboard now ]:->

Microsoft sells the Sculpt Comfort Desktop, but they are not listed here either: http://www.microsoft.com/hardware/en-us/help/windows-8/troubleshooting/mouse/supported-devices

Only the Sculpt Comfort MOUSE is there, the Keyboard and Desktop are not. Do you agree?

That can be called an ackward mistake made by Microsoft for sure.

Microsoft has updated hardware components.  They are not under obligation to support older hardware constructs when newer is available or when they discontinue an older version or other hardware series.  They aim for backward compatibility but this is not always possible.

For those with older hardware (yes, even the retail and online stores still sometimes sell outdates hardware) they are recommending uninstalling mouse and keyboard center and using the IntelliPoint Software instead.