AmbientShade - to fix this problem with your legacy content - invest in Netherworks Batch Material Convert program ($9.95 over at Content Paradise) - it will convert all of your .pz2s to .mc6s and place them in the materials folder for you - no muss, no fuss.  I converted a 40Gb runtime in less than 60 seconds.  I can not recommend it highly enough.  I couldn't live without it.

Going forward, there are 2 solutions for this problem.

Solution 1 - Storefronts enforce the current standard as part of the QA process.  If a product is for a modern figure (i.e. P9 or later), then the Poser 9 standards should be enforced.

Solution 2 - Use the customer review process.  As an example, if I buy a product for Dawn (a P9+ figure) that comes with material .pz2s instead of .mc6s, I deduct 1 star and I say WHY I am deducting a star. With some vendors, I could easily run out of stars.  I do the same thing with other stupid artifacts from the Poser 4 era that we are still dealing with today, such as:

thereisnoneedcompressthenameoftheproduct or

I_am_using_underscores_because_I_don't_know_that_DOS_is_dead

I gave all of my material names a leading MAT_ so the search function can't find it.

I use numbers as leading characters to force my customers to laborously hunt down something manually rather than use Poser's built in search function.

ANY MENTION OF MAC CONVERTER in the readme - for those of you who don't know, MacConverter was an OS9 product that converted Poser 3 content to a format Poser 4 could read.  New Mac users end up on a wild goose chase looking for www.softrabbit.de - which shut down over 10 years ago. I shudder to think how many sales this has cost vendors over the years.

I love the vendors, but I swear to god, some of them are their own worst enemies.