Should I use Windows File Compression?

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I have at least one good use for NTFS compression: Virtual Machines with Virtual hard drive images. Although the more advanced virtualisation programs have "dymanically expanding" hard drive formats where the image file only takes up the amount of used space on the Hard Drive, I sometimes like to use "raw" image files so that they can be accessed by more than one program.

These raw image files take up exactly the amount of space that they need, including any free space. This means that if I have a 30Gb virtual hard drive, with only 10Gb content on it, the image file will still take up 30Gb unless I NTFS compress it (in which case it takes up a little under 10Gb).

The effect on the VM? I'm kinda unsure. I suppose using a compressed image file might slow down hard drive access a bit, but I wouldn't have thought it would be too drastic. If there is a good way to scientifically test this I'd be interested to see.

I am using NTFS on my current PC and have file the compression tab unchecked on all my hard disk's but when i did a disk clean up, i wound up with alot of files/folders with blue names (compresed).

Now that is causing crash's and slowdowns on my computer.
my question is how to undo what windows decided to do on its self?

Hi, recently I've tried compressing files with the already installed application on Windows (WinZip). However, on my computer, the most it compresses of anything is maybe 10 kb, which obviously is pretty useless. I've tried using some other program I downloaded but it had the same result. But, when I use another computer, it compresses up to 50% of the file's size. And I haven't been using the files you mentioned as already compressed (mp3, jpg).

The article was good. (I also wanted to know about saving file space, and this helped!)

"I am using NTFS on my current PC and have file the compression tab unchecked on all my hard disk's but when i did a disk clean up, i wound up with alot of files/folders with blue names (compresed).

Now that is causing crash's and slowdowns on my computer.
my question is how to undo what windows decided to do on its self?" go to start-run-type cmd- in the command prompt type compact /u /s /a /q /i that should uncompress every file on ur disc but u have to re-compress those files u want compressed.

Good morning.
I can no longer open some of my photos ( a lot actually). I click on them and it says no view possible, even though they finish .jpg as they should. I believe I compressed these files when I did my last disk clean and therefore my current situation.
Could you tell me if I have indeed done what I think, or if not what you think, and if I have compressed all of these images, how to uncompress them.
I am on Windows XP Pro.
Thank you in advance,
Vladimir

Your answer helped me decide not to compress the old files in disk cleanup, but I was disinclined to do so because my really quite new computer takes a very long time to measure the 'compress old files' space and then a long time to do the actual compression. Does this point to some big problem with my old files , like a corruption or something?

Thank you, Jon, for the instructions on how to decompress all your files that windows did without your permission. I have now changed the setting to NOT allow that, but it was a nightmare trying to fix everything by hand until I saw you post. Your instructions worked, although I am obviously not as computer literate as you and it took a while for me to figure out exactly what to do for my situation. THANK YOU SO VERY MUCH, Leo and Jon!!! Donna in Texas

Is there a way to uncompress all the files that you compressed in a disk clean up, without having to go through and uncheck the box in the actual files properties menu? I noticed that after compressing them in Windows XP the compressed files are now blue. I did notice that once I did it, all the files that got compressed are now in blue font, when you look at them in the folders. That freaked me out a little. However, when you right click on the file, go to properties, then go down to "advanced" in the general tab, it has a check box for compressing the file. If you uncheck it, I guess it decompresses it, because it turns back to black font. Is there a way to do this for all the files like this, without having to do them individually? Thanks for your help, dude.

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You can select multiple files at once - hold down CTRL as you click on files to
add them one at a time, or hold down shift to select all files between the
first on you click on and the second. Or type CTRL+A to select all files. Then
right click on the multiple files and select properties. If you select a
folder, it'll ask if you want the change to be applied to all files in
subfolders as well.

Leo

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I have accidently compress alarge amount of my XP PRO NTFS drive. How do I undo the compression without going to each individual file and reseting its properties?

rgards
Martin B

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