[AndyCalling]

Many people will want to prepare by using the built in Windows system image function as advised in the Windows Central article to back up first. This is good advice, but there is a major issue you need to understand first. Otherwise your backup will refuse to restore with a cryptic error and the info you need is extremely hard to find on the net. At this point the general advice on the net is that your backup is corrupt and you're stuffed. This, however, may well be untrue.

Thing is, Windows (at least 8 & 7) cannot restore to a GPT formatted drive (all UEFI systems boot from a GPT drive, so most modern PCs) if your system image is saved to a GPT drive (all drives with a partition bigger than 2TB are GPT, so most modern backup drives). It will make the image fine, but as soon as you try to restore... cryptic error.

The solution is to move your backup image to a traditional MBR formatted drive (if your only option is >2TB then wipe it, reinitialise to MBR and make a small partition <2TB). Then the image will restore perfectly. It turns out Windows CAN restore an image to a GPT drive but only from an image stored on an MBR drive.

So if you're caught at your most digitally vulnerable, with your virtual trousers down and your recovery stick in hand, Don't Panic! Just remember this post.

...MESSAGE ENDS...
...KEEP CALM
AND
CARRY ON!...

[RumoredNow]

Thanks for the heads up.

[AndyCalling]

No probs. I really want to spread this one around because it is a time bomb waiting to go off at the worst possible moment for so many people and leads to loads of images being abandoned as corrupt.

Oh yes and painting your PC white will help deflect the heat but you'll need to pop it in to a paper bag as well to protect it from the fallout. Good luck!

[RumoredNow]

I believe my Install from a USB stick with manual Key input should be bombproof to restore my system in an emergency, yes? Then restore files from an external HDD...

[Guzzler3]

One more thing.

MAKE SURE YOU HAVE A WORKING RECOVERY DISK. Windows 7, Windows 8.x

This is just in case something, god forbid, happens during the upgrade and everything goes pear shaped, so you can get back to a working, legitimate copy, of your previous operating system.

[AndyCalling]

I believe my Install from a USB stick with manual Key input should be bombproof to restore my system in an emergency, yes? Then restore files from an external HDD...

It is where the files are stored, the system image backup files you made with Windows system image utility, that needs to be MBR if you are restoring to a GPT drive. So, your external HDD in the situation you describe needs to be MBR if you use a UEFI system.

[RumoredNow]

The install is on an 8GB USB stick prepared with this: Create installation media for Windows 8.1 - Windows Help and I will be required to give the Key to install.

The files on the HDD are just files. Not bootable. NTFS formatted, 2.5" laptop HDD in a USB 3.0 external drive enclosure.

[AndyCalling]

OK, you need the following:

1) USB recovery stick/disc or install stick/disc for Windows which must be UEFI bootable.

2) External or internal MBR HDD containing the system image data files (the ones you made when you imaged your system before you installed W10) which is not bootable BUT MUST BE MBR!

3) One destination boot drive on your UEFI PC which will be formatted as GPT.

None of this is necessary if you have an MBR boot drive (pre-UEFI).

I know, sounds unlikely, but when you discover I'm right you'll remember this post.

[GoneWithWinPC]

This is a good idea thanks

[thepolicecall911fordetails]

Could someone clarify this article?

(GPT files, etc)
My knowledge is not as vast as it should be. I do not understand some of the terminology expressed in this article. Anyone care to help?

[ReprobusR]

Back up your system; or atleast have a recent back up, if things should go wrong you simply restore !

[thepolicecall911fordetails]

Back up your system; or atleast have a recent back up, if things should go wrong you simply restore !

What about the fancy GPT file stuff?

[Skamath]

What about the fancy GPT file stuff?

MBR (Master Boot Record) and GPT (GUID Partition Table) are two different ways of storing the partitioning information on a drive. This information includes where partitions start and begin, so your operating system knows which sectors belong to each partition and which partition is bootable. This is why you have to choose MBR or GPT before creating partitions on a drive. for more info read THIS.

[nTrud3r]

I have my Windows 7 Ultimate disk ready in case the worst happens.
And I had to switch to MBR ages ago, Toshiba BIOS won't allow me to boot from external media, long story.

[Birgitte Sciarretta]

How do you know what kind you have then? Is there anywhere you can check it?

Nevermind, look here:

Hard Drive - GPT or MBR - Windows 7 Help Forums

Both mine are MBR so I guess I am good to go.

[EMINENT 1]

I had to do this on my ssd earlier.

No big deal. Went smoothly.

The first one is the method I followed:



Method #1:
1. Boot up to installation DVD/CD.
2. Click install but don't follow through.
3. Press SHIFT-F10 to bring up console.
4. Type "diskpart"
5. Once inside diskpart type:
-> list disk (find the one you want to convert)
-> select disk 0 (select the one you want from the list)
-> convert mbr (should take a second or two)
-> quit
6. Continue with install

Method #2:
1. Boot up to installation DVD/CD.
2. Click install but don't follow through.
3. Press SHIFT-F10 to bring up console.
4. Type "diskpart"
5. Once inside diskpart type:
-> list disk (find the one you want to convert)
-> select disk 0 (select the one you want from the list)
-> clean (wait an hour or so until its done)
-> quit
6. Continue with install