Hi all,
After some research into why some users upload material macros to the livedb, which gives problems like making all entries in categories invisible,
we've found that the issue is due to some people using single quote characters, eg ' in material descriptions or copyright fields.
So, naming a material like this: "My material that looks like a 'brownish' wood", and then uploading it to the wood category in livedb, causes the problem.
We will fix this in the next release, so for now, make sure you don't use any ' or other non alphanumeric characters, just to make sure.
Radiance