Just before the Christmas break, I was trying to unravel the following mystery:

DE> We have just migrated from a machine running DE> Zope with the ZServer to a different machine DE> running Zope with an Apache web server. But DE> we have a problem, namely, after copying over DE> the Data.fs ZODB to the new site, Zope cannot DE> find a needed (but installed) product (Navigator).

DE> This product definitely exists: DE> /Zope-2.1.0-src/lib/python/Products/Navigator DE> so why is Zope not seeing it? DE> i DE> From the manager view of the ZODB:

DE> Product at /optics / Control_Panel / Products / Navigator DE> There are currently no items in Installed product Navigator (Navigator DE> Product, Version 1.02)

Martijn Pieters replied:

That sounds like a working Product to me. Did it have items there before the move? What is actually not working, do you get tracebacks? [snip]

Yes, instances of Jonas' Navigator product show up with a pretty little bullseye gif image in the management view. I had a number of NavItems scattered throughout my ZODB with which all site navigation was handled. Now, these all show up as "link to a broken product". Further, the Navigator product no longer shows up in the drop-down "Add" selection box of the management interface. However, the pure-python Navigator product does show up in the management interface: DE> Product at /optics / Control_Panel / Products / Navigator DE> There are currently no items in Installed product Navigator (Navigator DE> Product, Version 1.02) so Zope has seen it in the /Zope-2.1.0-src/lib/python/Products/Navigator directory. (I take it from Martijn's last message that the "currently no items" blurb is standard for pure-python products.) I just re-verified that Navigator does work properly when added to a Zope running ZServer. The question: is my inability to use Navigator caused by simply copying over Data.fs from the old site, or does it indicate a problem with our Zope under Apache setup? There are no errors or tracebacks other than those generated from this pseudo- missing product.