Will Disabling Secure Boot Make You Loose Your Current OS?

[Vetorix]

I flashed an older version of windows on my USB Stick, which I want to access on my laptop temporarily. However, the USB Stick does not get recognized in the boot manager. I heard that I needed to disable secure boot so I can boot from the USB. My question is if I boot from my USB stick, can I afterwards plug out the USB and boot from my current OS (Windows 10, 64-Bit) like before without losing any files? Also, will I be able to enable secure boot afterwards?

Thank you for your Help.

[WAWood]

@Vetorix 

Techincally NO, that does not remove or disable the current OS installation.

What does disable it is changing the boot mode from UEFI to MBR, and vice=versa, because the boot mode has to remain the same one that was in place with the OS was first installed.

What MIGHT happen though (and I can not test this because I do not have a UEFI machine) is if you can even boot after disabling secure-boot.

Additionally, some of the newer PCs with both Secure-Boot and UEFI have the option to boot from portable devices DISABLED by default.  You should look through your BIOS settings and see if this is the case with yours before you try to boot from USB.