sephiroth091: well i was having trouble myself getting this to run, which seems others are having a likewise problem.
so i tried the usual of directx updates, driver updates, yet they didnt fix it.

in the end i visited safe mode and went to change your 3d video device.
i made sure it was set to direct3d and went thru to the end and hit run, which fixed the problem.

note visit your start menu, and find the gog folder in the clive barkers the undying folder you should find the safe mode option.

this is only one possible fix so it may or may not help most facing the problem.
which i posted it in the hopes that it may help someone out, since i faced this problem a few years back when i orignally played it, and just faced it yet again.

so goodluck to anyone who has any problems ^w^

Migromul: I changed the graphicmode. But anytime I try to start the game, I get the error-message "3d initialation failed".
Just (re)installed Directx 9.0c, but that didn't solve the problem.

Direct3d is supported and found with the auto-detection, however.

The game starts in 3dfx-mode. But I don't wnat to play in 3dfx-mode, if it is possible to play in d3d with 32bit graphic and wide-screen support. (16:9 1920x1080)

sephiroth091: just waking up at this time, where you able to get it to run fine? or still problems?

Migromul: As I said, if I try to start in direct3d, I get the error-message "3d Initialation failed" and the game doesn't start. If I start in 3dfx, the game runs (at least to the main menu. I didn't try to play in 3dfx) But I don't have the graphic-options of d3d.

sephiroth091: hmm so u didnt see if 3dfx mode would run?
seems like the game can be bit tricky to run, yet there are ways to get it running.
hopefully your able to get it running, trying different settings tends to work.

Migromul: Well, there are only 2 options: d3d or 3dfx... Since the official supported graphic-cards aren't on any PC nowadays.

the funny part is: d3d is found in the automatic graphic-settings. But if I try to start, I get said error-message. I realy don't know why. But perhaps I'll try to play it in 3dfx. And if I don't get it to run: only 1,49 €. This price I will forget... :) (The price was the only reason to (re)buy this game. I once played the retail-version until end.)

sephiroth091: hmm like i mentioned try messing around with the settings as thats what i did which led to it working.
also im unsure if you have them but, directx 9.0 and below might be required possibly.
so checkout directx relist as it adds to your updated one adding all 9.0 and below files.
which are sometimes required.

also i think if correct its possible to make an support ticket on gog right?
so maybe they would have some idea on an potential fix.

hoping you can get it running ^w^

Migromul: I played in 3dfx-mode. At least the game runs in that mode. I can't "mess around" with d3d-setting, because I don't get into the game in that mode... And I HAVE Directx 9. I play several other (older) games from pre-directx10-time.

Thanks for the help.