When I run the setup (UnitySetup-2.6.0.exe) it pops up with an error box (before it even gets going) and says I need a compatible version.
“The version of this file is not compatible with the version of Windows you’re running. Check your computer’s system information to see whether you need an x86 (32-bit) or x64 (64-bit) version of the program, and then contact the software publisher.”
So, since I’m using Windows 7 RTM x64, I figured I should go find the 64bit version. I looked all over, but there seems to be only one windows download. Since many people on the forum talk about how it works alright on their x64 version of windows, I can only conclude that either I overlooked the 64bit version, or someone messed up the install file.
Also: I downloaded it several times, so I doubt that it was corrupted to some weird point where it thought it was a 32bit only program. I also tried running in compatibility mode (xp sp2) and with administrator elevation (Run as Administrator). Not that any of these should matter, I just thought I would mention them.
I installed it on vista64 as well as win7 64, both with no problem (on Vista64 with uac completely disabled, in win7 64 with it on the lowest active level)
I would check if your antivirus plays smarty pants and moves around files as it tries to start the installer, rendering it useless (trend micro has such a sick fun about doing this kind of crap)
I would guess the problem is that you have a prerelease windows version that has some specific requirements or whatever, updating it to the current build should normally remove this kind of problem.
No antivirus running. The RTM in the windows version means released to manufacture, so it is the retail version. I just wanted to separate myself from people running beta/trial versions. Looks like it backfired 
Turns out for whatever reason, the unity3d.com site tries to figure out what version of windows you have. It must have failed and sent me the wrong version. Unfortunately the file names don’t have x86 or x64 appended to them, so I couldn’t tell this was the problem.
Using internet explorer 8 solved the problem. As such I went back and turned off Adblock in firefox, and whatda know. It sent me the right file that time. Anyway, I got it to download the x64 version, so don’t worry.
not sure if there is such a thing as a 64bit version as unity is a 32bit only app
You are right. It wanted to install into the Program Files (x86) directory. I don’t know whats up then. I suppose it might have sent me some other version? Or maybe just the install is x64? Who knows. All I know is that I downloaded it several times and always got the same error.
Then I changed things up and now have 2 versions that work. (as a side note: the ‘broken’ files also had broken icons. They showed some generic windows executable icon, not the Unity box thing)
sounds like the famous firefox induced download data mess … get it from time to time but only on very few webhosts actually. In those cases I normally drop the files into freedownloadmanager (ok thats a lie, I’m always doing that when I’m not prevented from doing so as 12 lines load faster than 1 line if you have a 20’000 / 5’000 VSDL connection ).
Never had any download problems with downloading from UT through FDM.
One Alternative Solution —>
