This was a strange problem, so I thought I'd share it in case it's helpful to someone down the road.
 
I was attempting to load an instrument into Kontakt 5 when I got the message "Your version of Kontakt is too old to load this file. You can update to the latest version by exiting Kontakt and starting Service Center."
 
"Too old" seemed an unlikely explanation, because a) this particular library is compatible with Kontakt 4 and higher, and b) I had just updated Kontakt a week ago. I ran Service Center just to be sure, and it confirmed that I was in fact up-to-date. (Even it had been out of date, it should still have been able to load an instrument that it created, no matter what the version.)
 
Turned out the nki I was attempting to load was corrupt. I had just saved it 30 minutes earlier. Because it was a stock instrument from a commercial library, I was able to reinstall it. I repeated the exact same change I'd made earlier and this time it saved OK, which I verified by reloading it.
 
I'm fairly certain it's a bug in Kontakt.
 
The moral of the story: back up your nki's before you edit them!
 
Moral #2: don't trust Kontakt error messages. "Your version is too old" seems to be a generic catch-all message when the program doesn't really know what the problem is.

A few days ago a ran into this problem, in my case the Kontakt Player was too old. My player version was 5.2 and it shows up to date at the Service Center. After writing to NI support and got a reply stating that there is a new 5.5 player available, I tried the Service Center again and it pick up the newer version. Seems at the time I hit the message (too old) the update wasn't available ? A manual download at the website shows 5.5x was dated 10 June.

Yes, the error message is misleading. My library that failed to load was the Session Horns that did work with older Player, among a few other Scarbee basses. Seems like there is some online update that kicks in to stop the library from running than actually can't run it ?
 
Previously my Guitar rig failed to run just because there is newer update available.
 

NI's inability to implement version compatibility is one of my biggest gripes about them. It's not because it's technically impossible, it's purely a marketing decision.
 
In this particular instance, however, it wasn't a version compatibility issue at all. Kontakt couldn't read the file (that it had just written!) and just threw up a generic message on the assumption that a software update would fix the problem, whatever it was.

bitflipper
NI's inability to implement version compatibility is one of my biggest gripes about them. It's not because it's technically impossible, it's purely a marketing decision.
 
In this particular instance, however, it wasn't a version compatibility issue at all. Kontakt couldn't read the file (that it had just written!) and just threw up a generic message on the assumption that a software update would fix the problem, whatever it was.

I agree that they are too much like Apple with little backwards compatibility and not so much like MS with quite a lot of backwards compatibility.
 
However, the problem might be something like this: The corrupted file has a version number with the Kontakt number in it. If it got corrupted, it might appear as if it was made with Kontakt version 20.2 and not the 5.x version you have. So in that sense your version is 'too old'.
 
A better message would be that this instrument's version is not compatible.
 
Quite often I found that Reaktor sample maps would not load into Kontakt in one version, they'd fix it in the next and break it again in the next.
 
And all these data structures are in binary, not something user-friendly like XML, SFZ, or whatever ASCII you like.
 
 
 
 
 

Updating NI products has really screwed me over in the past. If my NI plug-ins are working, I honestly avoid updating their products like the plague. I once updated Reaktor and I couldn't open the any instrument inside of Reaktor without it crashing, stand-alone and within SONAR. I couldn't open previous projects that used Reaktor. It was a nightmare. I re-installed it and didn't update it, and it works just fine, that is, as stable as you can expect Reaktor to behave.
 
In all honesty, it's my favorite plug-in company but it really seems like they're not really focused on the things that made their company's products so awesome.

I keep ALL installers...I don't leave them to the default, I have a special Downloads 
directory that I save them into, so that they are not deleted.  I then move them
to my storage drive under the appropriate heading  If I need to back up,
I just uninstall the latest version and reinstall the previous version.  I never worry
about doing updates.  9 out of 10 times they're fine, and usually address other
important issues.

Always better safe then SORRY...i.e...Replika 1.2.2

A tip here is to always run the standalone version of NI product if it exists, straight after the update.

I have a 4 drive system with that fourth drive (2TB) being for programs. I keep every downloaded installer even if it's available from a website. I've been caught too often needing a file and not having internet access for one reason or another.

I ran into something similar after buying ultimate 10. I had to erase older versions as they were loading up instead of the correct version. It threw me for a loop . All's good now..Very annoying indeed!