I just installed Fallout 1 on my Machine and get the following Error when i want to run Fallout 1:
"Not enough free Hard Disk Space. Fallout requires at least 20.0 Megabytes of free Hard Disk Space."
Ofc, theres enough Space on my HDD. About 18.5 GB on that Partition.
I am running Windows XP SP3, my PC is a X2 4800+ with 4GB of DDR2 Memory, an ATI 3870 and a 250GB Sata HDD.
Fallout is installed on the D-Partition here.
Any Clues how to fix that ? :(

You can try the general tip: uninstall, delete everything related to the install (excluding the installer of course) and then do a reinstall (oh, and after uninstalling try and restart, it may solve some registry issues).

Actually, after i installed Fallout 2 now also, Fallout 1 started to work oO
I tried starting it before 5 Times or so and i didnt work. Now it does.
So i guess my Problem got solved...in a mysterious Way.

It's because the game's a bit old, and reads the free space on your disk improperly. You can edit the free_space parameter in the fallout.cfg to 0, that should solve things.

Cheers, did what you said to prevent it from happening again :)

Unfortunately, that didn't do anything for me. I'm still getting he not enough space error.
EDIT: Oddly enough, its now working. Seems to be a very temperamental game xD

I've been having the same problem on XP SP3 as well. I can't seem to get the game to start unless I restart my system every time!

I have been encountering this issue as well, and the fallout.cfg fix doesn't seem to help it any. I may have created this file incorrectly, but given its simplicity I somehow doubt that...
I have been able to rectify the issue by simply deleting some files (clearing the recycle bin for one). This seemed to change the overflowed random number that Fallout is reading enough to get it to work.

I had the same problem, but I tried something that worked.
- Located falloutw.exe on your hard drive (default location: C:Program FilesGOG.comFallout)
- Right-click on that file and choose "Properties"
- Go to the "Compatability" tab
- Check "Run This Program in Compatability Mode For" and choose "Windows 95".
- Click OK.
That go it running for me. I haven't played too much yet, but so far, so good.

I ran into this last night as well. Given that it was my first GOG purchase and I was heading to bed I haven't fiddled with it much. I'll try some of these suggestions when I get home tonight. Thanks guys!

I deleted the installation file from the recycle bin and it started up...
oO

That happened to me as well. All I had to do was restart my computer, and it worked fine. Nothing to uninstall your game over.

I had this happen to me. After I installed the game, I launched it from the installer and it ran fine. I closed it to do some other stuff, and when I opened it from the desktop, I got this error twice. I figured I'd check the support info on GOG.com, but when I tried starting it again to get the exact text of the error message, it started right up. I haven't had the problem since. Weird...

This worked for me. Many thanks.

That CFG fix worked for me.. what is weird is that fallout was working fine yesterday. Go to start it this morning "Not enough free space." Did the editing of the CFG file and it works now.
hmm.