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I recently upgraded to Windows 7 and want to make an image of the installation in the event I need to rollback. I typically reinstall Windows every 6 months.

The installation as-is is over 10 GB, is this right? I don't have anything installed, no Office, no accessories.

How can I get it down to about 5GB, Windows XP used to be around 3 GB or so and would easily be backed up on a dvd.

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I believe my DVD burner supports dual layer discs, that'll get me about 9.4 GB. Now, if I can just trim out more fat. – Walter White Sep 2 '10 at 1:42
What is the best way for finding the drivers you aren't using? And, secondly, what is the best way to put them back? I am thinking if all else fails, can I simply move those files I won't use to another directory, write that to a DVD, then whatever is left, that'd be part of my image to restore to? – Walter White Sep 2 '10 at 1:43
I don't understand what you are trying to do with this, you are optimizing something you would need only twice a year. I don't think going through the hassle to get an expanded Windows installation on a DVD is worth it, the time difference between a clean install and a restore is just too small. You should instead look for a way to back-up everything now and then or take an image of a completed installation when you are done installing (thus with applications) and store that on an external disk instead of a DVD. – Tom Wijsman Sep 2 '10 at 2:19

You can't and 10GB does sound about correct.

The minimum specifications say:

16 GB available hard disk space (32-bit) or 20 GB (64-bit).

Windows has it's own backup utility, and more and more people are backing up to hard drive rather than CD/DVD as it has benefit for price, storage and speed.

I know it is a lot more than XP, but that is progress for you... With my first Windows XP machine, a 82GB hard drive cost me £150, now a 1TB is around £45-£50!

As for bringing it down, the only thing you can use is Vlite It is designed for Windows Vista, but I know people have had luck running it on Windows 7, that being said, I doubt you would want to cut out that much.

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+1 - Also for backups, look at NAS. You can get some good drives now for around $100/TB and use it to back up multiple PCs or Macs. – JNK Sep 1 '10 at 23:36
Thanks, but when I say backup, I meant the OS only. I re-image the system every 6 months. My files are stored on a Solaris server in a mirrored configuration with 3 copies. The Solaris box does NAS for me. – Walter White Sep 2 '10 at 1:34
if you want to reimage, I recommend you use your nas and the built in Windows tool located under backup and restore, it will allow you to create an image of your entire pc and restore. – William Hilsum Sep 2 '10 at 1:41

It is possible to get your installed state back on an installation medium using Windows AIK,
for mass installations this is fine. But for a single installation it isn't worth the time...

Not to forget it's better to look for the latest drivers and you will still have to update anyway.

Lots of years have passed between Windows XP and Windows 7...
The size of the OS has changed, but the HDD did too so that really shouldn't be a problem.

It's hard to decrease the default installation size without removing the necessary features.

I would suggest you to take another approach of backing things up. The installation size of Windows is a DVD, if you are trying to back-up your installation you might as well reinstall instead of doing a restore.

Try the backup and restore tags here at Super User and you might find a better solution to this,
if not, then it might be a valid reason to ask a new question on that issue... Maybe a duplicate appears?

Let's see where Windows is spending the most data in my case just to learn from it:

  • (21+ GB) Windows

    Please note that this is a 64 bit system thus any executable files can be bigger.

    • (6+ GB) WinSxS

      Read more about Windows Side By Side, see it as a core of Windows.

      Two big users I see: Speech Recognition (600+ MB), Windows Media features (200+ MB)

      If you will never use it you can compress or delete those files...

    • (5+ GB) System32

      The big users:

      • DriverStore (2+ GB) containing a lot Driver Installs as I used this OS on about 4 systems.

      • Files (1+ GB), seems reasonable if you compare this to a game.

      • Registry (700+ MB), I have a lot of software thus a lot of settings.

      • Drivers (100 MB)

    • (3+ GB) Installer

      Keeps a lot of installers for repair uninstall purposes, I compressed this folder.

    • (2+ GB) assembly

      Native images (per version) and a global assembly cache for .NET assemblies.

    • (1+ GB) SysWOW64

      The 64 bit counterpart to System32, only mimics the Files size.

    • (800+ MB) Microsoft.NET

      The core of .NET, contains a folder for each major version.

    • (500+ MB) Fonts

      These take quite a lot of space as well, can also be seen in WinSxS...

What we learn from this:

  • WinSxS, DriverStore, Installer and Assembly tend to grow over time.

  • Features that you might not need are available for easy installation without the DVD.

  • Windows has a much more stable approach to DLLs.

  • One can carefully apply compression he might need or delete things he never needs, take caution: While this applies for Speech Recognition and Windows Media Center (eHome), it might not apply for any random fire you will encounter and it is best to not tamper with those.

    As the Side By Side article stated:

    If you delete components from the WinSxS folder like the manifets or the assemblies, etc, you could be in trouble. Each system would react differently. What may work for one could break another! For instance, if you install a program that requires that particular assembly, which you may have deleted, then that program will just not run! Compressing the folder is also a no-no, as it could cause problems during Windows Updates or while installing a Hotfix.

  • After using this installation intensively for a year, it seems time to do a reinstall in the near feature.

Please note: The Pagefile takes space too!

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I don't use pagefiles, I keep everything in ram (6GB). If I am doing that much stuff at once, I don't believe I can keep up with all of that nor will my CPU be able to. Why can't you only install the drivers you need? It looks like if I had my way, I would remove (6, 2, 3) or 11 GB. – Walter White Sep 2 '10 at 1:38
The initial driver set that comes from the installation isn't that, the drivers that come with Windows Update or from other installs are the ones that do increase the size of the folder. – Tom Wijsman Sep 2 '10 at 2:15

For perspective:

  • MS-DOS = ~1MB
  • Win3.1 = ~4MB
  • Win95 = ~40MB
  • Win98 = ~400MB
  • WinXP = ~4GB
  • Vista/7 = ~16GB

Looking at the growth here, it's not exactly out of line. IIRC, Windows 7 is actually already smaller than Windows Vista, because they removed a bunch of drivers included with Vista that usage data showed just weren't necessary.

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Official specs requires 16 GB of free disk space for the 32 bit version, but 64 bit version (that is now far more common in my experience) officially requires 20 GB, so 10 GB after a clean install are reasonable for W7 standards.

Btw it will enlarge quickly with updates, so consider carefully if you absolutely need a back-up as small as possible or if you would better start with all patches applied before saving the system.

Probably the cheapest media for initial system backup would be a spare old 16GB USB stick, that would also be smaller (and probably faster) than a set of DVD.

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