Mine said that too when I first tried it. I closed the Explorer window, opened a new one and re-tried it, and it all worked fine.

I'm having this same problem. My user account is the admin account. Winxp 32-bit service pack 3 as well. Even running regsvr32 in the command prompt throws this error.

Edit: I DO however have the non-gold version of Thief installed on my computer, which runs perfectly. IDK if I've ever seen a cutscene in it, but the game plays, whereas the GOG version won't even install...

Hmm, the GOG installer not even finishing is an odd one. Make sure you do not install in the default directory (Program Files), but under WinXP that shouldn't be a problem. What error message do you get? Maybe it's a bad download?

I've tried downloading it twice. I tried running the installer in Win98 compatibility mode. I tried turning off my avast! data shields. I've tried using "Run as" to disable protection against unauthorized data execution. I've even tried opening command prompt and registering the freaking DLL manually.


One important note, the error code changed when I disabled avast. With avast running, the code was 0x5. Without Avast, it was the same as when I ran Regsvr32 in Command Prompt, which was error 0x8000ffff just like OP.

I'm pretty sure, at this point, that it has something to do with SP3's data execution protection system, but I'm not sure how to go around that. The only other possibility I can think of is that we both have a virus or a corrupt system file or something, and unfortunately, I don't have my Windows disk to run SFC to verify that I don't.


Maybe we have to go through a process similar to this to enable us to register the necessary DLLs:
http://kb.backupassist.com/articles.php?aid=3001

The only problem is, I've been out of the computer-fixing business for about 4 years now, and I'm kinda scared I'll royally screw up the computer I do my homework on...

Anyone volunteer to be a guinea pig?

I have also confirmed that my Thief TDP 1.33 install does work, and has cinematics playing. However, this is not GOG's thief Gold... :(

Update: I have just installed a codec pack, which went off without a hitch, which proves that there's no problem with registering DLL files. Also, I disabled data execution prevention for the setup exe file. That didn't help. It still will not install.

I did find something interesting though. When I removed my ir50_32.dll file from the windows/system32 directory, it created another, but couldn't register it, and when the install failed, it was deleted, so I replaced the original.

I checked the Windows Registry, and the DLL file is, in fact, already registered. But that shouldn't make a problem, unless GOG's installer is very, very poorly coded.

The only other thing I can think of, besides trying to remove more protection (see my above posts), is to try and delete Thief: The Dark Project. and/or to run SFC to make sure absolutely nothing is funky with my windows install. Beyond that, I'm at a loss.

dudalb, do you have the old version of Thief already installed?

I'd recommend installing in Safe Mode, you don't need any drivers or startup software to install it.

Now there's an ingenius idea I would have never thought of! I'll get back to you.


Also, I talked with GOG support. They say that this kind of error should not stop the install, so I'm guessing it's an installer limitation... I'm waiting to hear back from their response after I verified that it didn't install.

Installing from safe mode netted the same result. Is there any way I can force an install? The "ignore" button simply doesn't show up...

No, I'm out of ideas I'm afraid - if GOG's installer is the problem, then that's out of my understanding. Hope they get back to you soon.

I believe I ALMOST have a work-around.

It's incredibly painstaking, though... I must have run the installer about 15 times and grabbed each file individually as it unpacked them. Then I went to my Thief: The Dark Project install and began converting it file-by-file.

But now I get some sort of error every time a cutscene plays or the game loads, that kills the game. Hopefully one of the community patches fixes this.

I got the game to install. Seems in my case there was some conflict between the Indeo Video Codec file (Ir50.32 dll ) I already had on my computer and the one that the GOG installer was trying to to install. I simply (after backing it up outside the sys32 file) deleted the dll and, lo and behold, it installed perfectely.
Still surprised it simply had a catastrophic failure instead of automatically overwriting the file or giving me a 'The install programs wants to overwrite this file.do you want to go ahead" type message. . Wierd You might want to try the ddfix patches that are pretty much standard to get Thief to run on a modern computer. THere are links to them all over the GOG THeif message page.

In their Email apply GOG suggest I run it in Admin mode, which, since I am using XP 3 in which admin mode is only used in a network situation,(unlike Vista or 7,where it seems to be required to run just about anything) does not make much sense.

Yeah, admin mode didn't work for me.


HOWEVER, I do believe I was successful in copying all of the files over from a gold install WHILE IT WAS INSTALLING and pasting them in my TDP install. I really don't know for sure, as it deletes them when it fails, I may only have a partial copy. I tried moving the codec file in question, like you suggested, and it still would not install...

An interesting note, Thief kept crashing on me if I used the K-Lite codec pack, but as soon as I deleted it, it ran fine.