I have an odd problem: An upgraded 2010 installation was working fine for a year or so - and as always "nothing" was changed recently (a small webpart was deployed).
Most of the Site collection (with several sites) are still in the 2007 layout. Some sites are already upgraded to 2010 via visual upgrade.
All sites with 2010 layout are fine, but the 2007 experience a problem:
- All links are gone from the quicklaunch (left) menu (View all site content is still there)
- When trying to edit the navigation via Site Settings > Navigation, no changes are applied to the quicklaunch
- The only way to add new items to the quicklaunch is via the obscure
_layouts/quiklnch.aspxpage - I can add links via that page, and they are displayed correctly
Again: Pages with 2010 layout don't experience this problem.
I'm looking for pointers where I should start looking. Did some navigation provider break? Did the 2007 masterpage change magically (no changes I know of were made) - but why does it display links added via