Ubuntu Wubi install is freezing / stalling / hanging on iso download

can I do a Wubi install with a manual download of the big file that is required and which Wubi seems to hang on?

Yes. If you put the ISO image for the version (and architecture: 32 vs. 64-bit) that you want to install in the same folder with Wubi, and no other ISOs are in that folder that might be inadvertently selected instead, and the ISO is not corrupted, then Wubi will use it instead of attempting to download the Ubuntu ISO itself.

Specific steps:

1. Make an empty folder in Windows.

2. Put wubi.exe in it. Make sure it's the version of wubi.exe for the specific version of Ubuntu you're using. (Each release has its own wubi.exe, though 32-bit and 64-bit versions of Ubuntu don't have separate wubi.exe files.)

   • Here's wubi.exe for Ubuntu 12.04.5 LTS. If you already have an earlier 12.04 ISO image, I still recommend getting a 12.04.5 ISO file and using that.

     But if you want to install from an earlier ISO, you can. You should then install updates in the Update Manager, once your Wubi system is installed--which you should do anyway, even if installing 12.04.5.

     I don't know if the 12.05.5 version of wubi.exe will recognize the older ISOs as correct.
     If not, some of the earlier wubi.exe files are on the old-releases server.
     [12.04 (original), 12.04.1, 12.04.2, 12.04.3]

   • Here's wubi.exe for Ubuntu 14.04.1 LTS. My guess is that this would work with the original release ISOs of 14.04, as well.

   The wubi.exe files themselves are small--even if you have a very slow Internet connection (e.g., dial-up), that's no reason to attempt installing with an older (or wrong) wubi.exe.

3. Put the desktop ISO file in it. (It's fine if you do this before step 2, of course.)

   Make sure it's the ISO image for the release and architecture you want to install, and that the release matches the release of the wubi.exe file you are using.

   • Here's the 32-bit desktop ISO for Ubuntu 12.04.5 LTS. Or you can get it with bittorrent.
   • Here's the 64-bit desktop ISO for Ubuntu 12.04.5 LTS. (Here's the torrent for that one.)
   • Here's the 32-bit desktop ISO for Ubuntu 14.04.1 LTS. (Here's the torrent.)
   • Here's the 64-bit desktop ISO for Ubuntu 14.04.1 LTS. (Here's the torrent.)

   Whether you should use the 32-bit or 64-bit version is not determined by whether your Windows installation is 32-bit or 64-bit. A Wubi system is installed on a rewritable disk image inside your Windows partition, but it doesn't actually run as a Windows program when you use it. So you can use a 64-bit Ubuntu system with Wubi on a 32-bit Windows system, and vice versa.

   Of course, if your computer has a 32-bit processor, you won't be able to run the 64-bit version of Ubuntu. And there are limited circumstances under which you might prefer to run the 32-bit version even when your hardware supports 64-bit. If you're not sure which to get, see What are the differences between 32-bit and 64-bit, and which should I choose?

4. Run the copy of wubi.exe that you've put in the folder with the ISO image you want to install from.

   If Windows is configured to hide file extensions when displaying files, this may appear just as wubi. That's fine.

   If UAC is enabled, as is the case on the Windows desktop OSes that support UAC (so far, this is Vista, 7, 8, 8.1), make sure you run wubi.exe as administrator. You can do this by right-clicking the wubi.exe icon and clicking "Run as administrator."

If Wubi still cannot use the downloaded ISO image, and the ISO image version is paired correctly with the wubi.exe version, two problems are likely:

1. Especially if Wubi failed early and/or still tried to download a new ISO image, check to make sure your downloaded ISO is not corrupted. You can do this by comparing its checksum against the official one. If you're only worried about inadvertent corruption (and not deliberately malicious modification), checking the MD5 hash is sufficient. (See also this article.)

   As of this writing, there's been a delay in adding the Ubuntu 14.04.1 and 12.04.5 hashes to the UbuntuHashes wiki page. You can view them

   • in the MD5SUMS file for 12.04.4 and 12.04.5 (if you're installing Ubuntu 12.04.5), or
   • in the MD5SUMS file for 14.04 and 14.04.1 (if you're installing Ubuntu 14.04.1).

   For convenience, the relevant lines are:

   • 12.04.5, 32-bit
     09eb43dcfce2b7246bdd6e8108e755df *ubuntu-12.04.5-desktop-i386.iso
   • 12.04.5, 64-bit
     48b4edf237c489eebbfef208c2650d11 *ubuntu-12.04.5-desktop-amd64.iso
   • 14.04.1, 32-bit
     a4fc15313ef2a516bfbf83ce44281535 *ubuntu-14.04.1-desktop-i386.iso
   • 14.04.1, 64-bit
     119cb63b48c9a18f31f417f09655efbd *ubuntu-14.04.1-desktop-amd64.iso

   ^{Anyone verifying the ISO images based on security considerations should use the official sources linked above and not rely on the copied hashes in this post. In that case, you should really verify the SHA1 hash (12.04.5, 14.04.1) or SHA256 hash (12.04.5, 14.04.1) instead of relying on MD5.}

   If you know your ISO file is correct (for example, by checking its MD5 hash yourself) but the Wubi installer keeps rejecting it, you could run the Wubi installer with:

   wubi.exe --skipmd5check
   

   This makes it attempt to proceed with the installation even if it thinks the local ISO file is wrong. One way to do this is from a Command Prompt launched as administrator. (The .exe extension in the command is optional.) You'll have to cd to the appropriate directory first:

   
   ^{Having put wubi.exe and ubuntu-14.04.1-desktop-amd64.iso in a folder by themselves, I start a Command Prompt as administrator (since UAC is enabled on this Windows system) and run cd C:\Users\ek\Downloads\wubi (you'll have to replace this with the correct location on your system) followed by wubi.exe --skipmd5check.}

   Another way to run wubi.exe --skipmd5check is to make a shortcut to wubi.exe (right-click it wubi.exe, click Create shortcut). Then right-click the shortcut and click Properties. In the textbox labeled "Target:" add --skipmd5check to the end (make sure there's a space between ...wubi.exe and what you added).

   
   ^{Running wubi.exe with the --skipmd5check command-line option by creating a shortcut and modifying the Target field in its Properties window.}

   Then run the Wubi installer through the shortcut you created.

2. Wubi doesn't work on UEFI systems with GPT disks. If your computer shipped with Windows 8 or Windows 8.1, you can't install Ubuntu with Wubi inside those Windows systems. (If your computer came with a different OS and you installed 8/8.1 yourself, you probably can.)

   For these UEFI systems, you'll have to install Ubuntu in the "regular" way. (That is, to coexist with Windows it will have to be installed with its own partitions, alongside Windows, and not as a Wubi system existing inside a partition belonging to the Windows system.)

   ^{You might succeed at creating a Wubi system inside a UEFI/GPT Windows 8/8.1, but it wouldn't boot once you created it. (This is not specifically a Secure Boot problem; even with Secure Boot turned off, it should not be expected to work.) I'm including this information not out of suspicion that this is the cause of your current problem, but because it's highly relevant today--that is, mainly for the benefit of other readers who come along.}

   ^{On the other hand, if you are using a preinstalled Windows 8 or 8.1 system, maybe Wubi did actually get past downloading the ISO automatically and failed while installing.}

Further reading:

• WubiGuide, especially How can I use a manually downloaded ISO?
• Windows installer for Ubuntu 14.04 LTS onwards, specifically Rinzwind's answer (and the post by Dima it cites)