Hard disk suddenly shows a 100GB more free space

I've recently upgraded to windows 10 home version from windows 8.1 . My hard disk space before the upgrade was around 50GB. After the upgrade it was reduced to around 32 GB. I figured it was just because windows was storing some of the older files temporarily to allow for a rollback.

Today, i started my PC after it got shut down due to low power, the hard disk is suddenly showing 130 GB free space.
All programs seem to be in place working fine. I just couldn't figure out where the additional space came from.

Can anyone please tell me if there's something i need to be worried about

Thanks

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When did you upgrade to Windows 10? If a month has past since then the windows.old file that would allow you to rollback to your previous version has been automatically deleted. It is very large and might account for the extra space

I've updated three so far and the windows old has been about 19gb in each case. Also, I had to delete them manually, it was not automatic. I did not wait for Microsoft to do it for me.

Pagefile (virtual memory) change is a guess, but can be a possibility.By default set to let windows decide.

I've recently upgraded to windows 10 home version from windows 8.1 . My hard disk space before the upgrade was around 50GB. After the upgrade it was reduced to around 32 GB. I figured it was just because windows was storing some of the older files temporarily to allow for a rollback.

Today, i started my PC after it got shut down due to low power, the hard disk is suddenly showing 130 GB free space.
All programs seem to be in place working fine. I just couldn't figure out where the additional space came from.

Can anyone please tell me if there's something i need to be worried about

Thanks

Looks like the Volume size is being misreported due to the power outage.

... If a month has past since then the windows.old has been automatically deleted.

OMG!!! SO I'm 47 (or is it 48?) years old, was TOTALLY STOKED with the release of MS-DOS 6, started my love of Windows in the 3.0 days (yes, even before 3.1) and my first modem was 300 baud. I met my first partner in 1985--on a dial-in, one-user-at-a-time BBS, my first HDD was 20 MB (yes, MEGABYTES) and cost nearly $600. My last partner works for Microsoft and I've spent more than a little time there hanging out with various teams on the campus, happily accompanying anyone who asked to the Company Store for whatever goodies I didn't yet have....yes, a good 30 years of computing experience, most of it run in some way by Microsoft. And I am just now, on the morning of October 23, 2015 learning the the windows.old file self-deletes in a month! I've never let it stay around more than a day or two but I like living dangerously. Still, thanks to you, Elizabeth I've learned something; I've learned I'm not as smart or as informed as I thought!

Well SmartGuyDumbPc, I seem to have you by about 20 years and multi releases of DOS (started with 1.1? or 1.2? and two 180KB 5 1/4 floppies and eventually saw my first massive 10MB HD).
Maybe it's just senility but I think you owe Elizabeth an apology unless you are even stupider and more ignorant than you now appear to be. I have an IQ that Mensa finds acceptable but still learn something new almost every day and hopefully I will never berate any source of information offered in good faith.

Today, i started my PC after it got shut down due to low power, the hard disk is suddenly showing 130 GB free space.

The default "shutdown" setting for Windows 10 is "fast startup", which means Windows doesn't really 100% shutdown, turn the computer 100% off and hand control over to the bios for the next startup. It is more of a hibernation were most of the operating state of the computer is stored in a hibernation file. I wonder if when recovering from the low power shutdown that the hibernation file was not used for startup and thus deleted. The next proper shutdown might recreate that file and take up the hard drive space again.

If nothing is missing that you can tell or that seems to affect windows, I wouldn't be concerned about it - could also just be a routine self cleaning of temporary files.