System image creation failed overfills HDD

Hi!
I've just bought a new computer. I'm trying to make an image of the system inside a partition of the internal Hard Disk. At the end of the process it says that the backup is failed because the shadow file is on another volume.
Letting this error apart (I could copy the image on an external hard disk), the problem is that any time it failed I got my hard disk space occupied by new "phantom" 45gb.
I deleted the partition where the systyem image was meant to be after any failed attempt, but each time the hard disk got filled up by additional 45gb. I tried to run a disk cleanup but it didn't help.
So I find myself with a brand new computer already with a lot of space weirdly occupied. Anybody can help me finding the solution?

Thanks much in advance

Welcome to TenForums @Whaleheart

What software are you using to try and make this system image? Windows' own 'Backup & Restore' or something else?

It would help with diagnosis if you could post a screenshot of your Disk Management so we can see what disks and partitions you have available to you.
Disk Management - How to Post a Screenshot of

Hi, thanks for your prompt reply!
I used the windows disk management.
Actually that sounds funny, I waited before posting here to find the solution by myself, I used the disk cleanup, restarted the pc and looked on the internet and it persisted. Now the pc says to me again the correct amount of GB I should have had, that's crazy. Thanks very much anyway.
But curreny I hace another little problem.
I created a partition on mu external drive, i saw it was too big and I shrinked it. Now I wanted to extend the main partition to gain those GB shrinked but it says it's impossible to do that and it remains with 25 gb unused...

Solved! Thanks!