Should I format external HD before creating a hard disk image on it?

I use Windows 7 professional 64 bit edition. Im a novice user who is doing this for the 1st time.
I intend to use Macrium Reflect Free edition to store an image of my C drive which is the only partition I have, (931 GB ( of which 537 GB is free) ) on an external HDD which is of Sony, 1TB & Fat32 formatter.

But am I supposed to format the external HDD before attempting to create an image on it? The external HDD already has nearly 400 GB contents on it, & i cant wipe it off. Does the imaging process wipe it off? Or am i expected to do it, before starting the imaging process??

& also how much space is the image going to occupy roughly??

& one more doubt.. What is meant by compression? If I go for a "medium compression" option, will it affect anything when I restore from the image? I mean.. Will it affect the quality of the media files when I restore from the image?

I'd be highly thankful if someone could guide me on this.. Please..

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RebeccaValentin said:

I use Windows 7 professional 64 bit edition. Im a novice user who is doing this for the 1st time.
I intend to use Macrium Reflect Free edition to store an image of my C drive which is the only partition I have, (931 GB ( of which 537 GB is free) ) on an external HDD which is of Sony, 1TB & Fat32 formatter.

But am I supposed to format the external HDD before attempting to create an image on it?

No reason to do that. The Macrium image will be just one more file to store, albeit a big one. Just like a huge picture of your cat. You don't need to re-format your external just because you want to store a picture of your cat on it. "Create an image" simply results in an image file that needs to be stored somewhere. It's "image restoration" that wipes stuff out.


The external HDD already has nearly 400 GB contents on it, & i cant wipe it off. Does the imaging process wipe it off? Or am i expected to do it, before starting the imaging process??

No and no. Image restoration would wipe the partition to which the image is restored, but simply storing an image file wipes nothing--no more than storing the picture of your cat onto the external would do.

& also how much space is the image going to occupy roughly??

Roughly 50% of the occupied space of the imaged partition.

If your C is 300 GB, with 100 occupied, figure about 50 GB for the image file.

If you have a "System Reserved" partition, you probably need to include it in the image file, along with C. Both partitions in a single file is fine.

It's unclear to me whether you mean your external is 931 GB or your internal C is 931 GB.



& one more doubt.. What is meant by compression?

It's just a way to make the image file smaller. You don't have to understand the complexities of it.

If I go for a "medium compression" option, will it affect anything when I restore from the image? I mean.. Will it affect the quality of the media files when I restore from the image?

No and no. The files will decompress to their normal state when restored. The Macrium default is medium compression, which typically results in the 50% I mentioned above. If you used high compression, the image file would be smaller, but it's difficult to say how much smaller. Certain file types are more compressible than others. For that reason, the 50% might turn out to be 40% or 60% in your particular case.

The image file will have an mrimg extension. You can move it around or copy it like any other file. I'd suggest you back it up like you would any other critical file and make a new one perhaps monthly. Keep 2 or 3 on hand--or more if you like and have sufficient storage space.

You can make image files smaller by minimizing what you keep on C. So it can be advantageous to keep personal data files on D or E and use C purely for Windows and applications.

My C partition has only 40 GB occupied. My Macrium images are now around 18 GB--just under 50%. It takes about 3 minutes to make a new image file. Restoration would take a bit longer in my experience.

The most important thing for you to understand is that the image file is not very useful until it's restored and that you need to make "recovery media" from within Macrium so you can boot your PC and restore your image file if your hard drive drops dead. Make the recovery media and confirm that it will in fact boot your PC. Ideally, you should practice image restoration so you are familiar with that procedure---rather than try to figure it out when you are in a disaster situation. Maybe you have a spare hard drive you can restore to for testing purposes?

RebeccaValentin said:

I intend to use Macrium Reflect Free edition to store an image of my C drive which is the only partition I have, (931 GB ( of which 537 GB is free) )

& also how much space is the image going to occupy roughly??

It looks like you are using approximately 400 GB on C. I'm still using V5 on the PC I'm currently using and my default compression runs at around 40% so I think your image would be around 0.6*400 = 240 GB.
It looks like you have approx 500 GB free on the external so you should be ok.
If you are using a USB 3 external HDD to store the image then I'd expect it to take 40 min+

Macrium V6 default compression may be slightly better. I have V6 on another PC but I don't have access to it at the moment.

RebeccaValentin said:

( My internal is 931 GB, of which 537 GB is free.. My external is 1TB of which nearly 400 GB is free.. )

I can only use a bootable USB (32 GB) for the rescue media. So first I have to create a rescue media on my bootable USB, then boot through it, then plug in my external 1 TB HDD to locate the image stored in it, & restore the image from it, to the my internal drive. Am i correct about the process?

Yeah, that's about it.

You might want to post a screen shot of Windows Disk Management, so we can see your partition layout and confirm what partitions need to be imaged.

Be sure to test the rescue media so you know it works.

When you boot from it, you will land in the Macrium interface that will look just like the Macrium interface you would see if you opened Macrium normally on your working hard drive.

If your hard drive is working OK and you just want to restore Windows because it's significantly fouled up, you can restore by booting the PC normally (without using the bootable USB) and starting up Macrium directly from the hard drive.

Looks like your C partition is using about 394 GB. Don't forget to include System Reserved, which is very small.

So, an image file of your C will be around 200 GB. Your external has "nearly 400 GB" free-----so you may not be able to store more than 1 image file on the external--depending on the exact size of the image file.

I would not want to have only 1 image file. Your alternatives would be to make more empty space on the external or to reduce the occupied space on C or to use high compression within Macrium when you make the image file. I'm not sure how much smaller the image file would be under high compression if you use it.

394 GB is quite a large C. Maybe your personal data is on C? You could move the personal date to D partition on the same drive if you wanted. That might make C much smaller and allow for more image files to be stored on the external. At 394 GB, it might take a half hour or more to make an image file. It takes me about 3 minutes to make mine--but my C has only 40 GB occupied.