Well ... while creating my new char (a "survival of the fittest"-believing anarchist). Originally he was meant as a possesion-based shapechanging mage. For several reason he should have some cyber- and bioware (character concept can be posted if wanted, though not important for the question itself).

Well ... Does Cyber-, Gene- and Bioware give any benefits while in critterform? As far as my understanding goes it should (as far as possible) because it is paid for with essence. If not: What happens with the ware? Still present in the body but unfunctional? The best method for extracting cyber from the street sam (Hey, he's a cute doggie now and his ware lies around!)?
Or would you rule it on a "item for item"-policy? E.g. the platelets might work but the rigger control won't.

AFIK, any 'ware stays with the person, but provides no benefit. One of the things 3rd ed really did do better than 4th. No more turn-to-goo cyberware harvesting.

Example for thought: the team mage turns the sammy into a snake to get through some pipes...snakes don't have limbs, so what happens to his cyber legs? what happens to his meat arms? why would the answers be different? If the cyber got left behind, what happens when he changes back?

Yet it's pretty obvious that the hydraulic jacks installed in the cyber legs isn't going to work while shapechanged.

So you can either come up with a case by case rulings for what works and what doesn't, or you can make a blanket ruling that might be inconvienent, but isn't designed to screw over the players.

Afterthought:

The closest thing to a counterexample would be that that character's magic or resonance apparently continue to work while shapechanged (note that possesion works differently - special attributes get overwritten without the channelling metamagic - so no possesed technos hacking.)

Sure - but he'd have a problem with wards or patrolling spirits.

If it is paid for with essence then it changes, too. Under the influence of Shapechange 'ware is just regular critter flesh.

JBlades, he said 3rd did it better than 4th. Why? Because the spell didn't exist in third. In 4th, its back. Thusly, 3rd does it better, because the abuse isn't possible.

Bingo - they did have petrify (which affected cyber) and I know a few GMs who houseruled turn-to-goo back into the game using petrify's rules, and that worked fine. 4th ed brought both back officially, but unbalanced them by breaking the "paid-for-by-essence = part-of-body" guideline.

yeah I was surprised to see turn to goo back

personally, i'd rather have seen turn to stone make a return . . because as a sammy i don't like the thought of someone just, kinds, you know . . ripping out my eyes and the such for example . . also there was a funny little translation error concerning turn to stone or what's it called in german . . in english it states that the subject isn't consius(sp?) while the german version says the subject IS concious(sp?)

English spell was called Petrify. But did exactly that, turn them to stone.
Conscious is the right spelling.

That is a nice little error. Nasty nasty torture time while they're stuck and can't move.