Failed to determine definition for Feature...

I was working on SharePoint case and found myself staring at the logs... again :-)

I found 11 lines with "Failed to determine definition for Feature with ID..." and it was repeating quite often. And that error is something new for me... And if you have stared SharePoint logs for an year that's really amazing! Exact error messages were like this:

...
Failed to determine definition for Feature with ID '065c78be-5231-477e-a972-14177cc5b3c7'.  Skipping this feature for element querying consideration.
Failed to determine definition for Feature with ID '0806d127-06e6-447a-980e-2e90b03101b8'.  Skipping this feature for element querying consideration.
Failed to determine definition for Feature with ID '2510d73f-7109-4ccc-8a1c-314894deeb3a'.  Skipping this feature for element querying consideration.
Failed to determine definition for Feature with ID '00bfea71-dbd7-4f72-b8cb-da7ac0440130'.  Skipping this feature for element querying consideration.
...

So I searched (with Vesa Juvonen) those guids from 12\TEMPLATE\Features-folder and found out that those features were actually Enterprise Edition features (like Excel Services). MOSS "couldn't find" those features even if they were OOB features. The reason for this was actually quite understandable... since there was a site collection that has been moved from MOSS Enterprise to Standard. And in Standard you don't have those Enterpise Edition features available even you have those activated in you site collection. The lesson of this exercise was... don't mix and match editions :-)

Anyways... Happy hacking!

J