Why does my Surface3 have a windows.old file on it?

[gnd1]

I was tryingto clean up some files on the S3 and went into Control Panel- Free up disk space to clear some stuff out. Took forever,,but on the list was a 3.5G windows.old entry. Now if I am not mistaken, this file is on computers that have been upgraded from one version on widows to another. Like 7 to 8. So why is this on a new tablet? I ran this one time before, and did not notice it. The only thing that I can think of, is that it has to do with the Windows10 preinstall thing. But I never got the chance to sign up for that> I noticed the icon in the tray one day. When I went back to sign up for it, the icon was gone. Why would that disappear?

 

[johnson_patrickw]

Did you install the Preview?

 

[gnd1]

No. not playing with any trials of Win10. I don't think that I even signed up for the "Get Windows 10" pre load.

 

[johnson_patrickw]

Does the windows.folder have anything in it?

 

[gnd1]

Ok. weird. I deleted most of the stuff suggested (not the 3.35G of other windows files) and the icon for Win10 reappeared on the task bar.