I can not choice USB device

Hallow all.
I have problem about Qube os install. I success install Qubes os to USB(new one :64gb). And I can go install page by USB.
But, USB is not an option for the installation destination device.
There is only PC device(almost 200gb). What should I do?
Please help me.

I put a 250GB SSD into a Sabrent USB adapter attached to an HP Z420, booted Qubes 4.2.0rc5, and my install is running now. I’m a relatively new user, I didn’t think Qubes would even install to USB, but it does.

You’ve said nothing about the hardware you are trying to use to do this.

Uhmm. thank you replay. You install hard disk of PC? Actually, I did install to PC hard disk. And, I can not use other than that Qubes OS . I can use only Qubes os on my PC. I want to boot USB and show Qubes OS. And, I can use PC normaly .
Can I do this? or not? sorry, my English.

I am doing experiments with Qubes on a spare workstation. I have tried a variety of things with it, using both internal hard drives and an external USB device. The external device worked for me, but only after I purchased a PS/2 keyboard and mouse for the machine in order to be able to use Qubes. Previously I was unable to make Qubes work using a USB keyboard and mouse.

You have not yet described the hardware you are using. The make and model of the computer would be useful to know.

Oh,sorry. My PC is Microsoft surface 7.
I have never used an SSD, but can I buy a new external SSD and install Qubes OS on it? Also, when I want to use Qubes OS while using my PC as usual, is it possible to run it from an external SSD like a USB memory?

There are only a few Microsoft Surface devices that have an HCL (hardware compatibility list) report, the newest is a Surface 3. Look at the reported issues for each install.

I put Qubes 4.2.0rc5 on a thumb drive, I used a 250GB SATA drive in a USB enclosure, and installing on that worked. This was a desktop computer with a PS/2 keyboard and mouse.

There is no report saying Qubes will NOT work with a Surface 7. But there is also no report that it does work. You are doing something brand new.

Did you try selecting Qubes OS installer with kernel-latest menu entry?
Did you only try Qubes OS 4.1.2 or Qubes OS 4.2 as well?

I installed Qubes OS 4.1.2. I think this is latest one that time.

I think surface is OK for Qubes os.
The problem is that there is one option for the installation destination device. And this one is PC storage. If I choose it, I use Functions other than Qubes OS cannot be used.
Because I want to more option for the installation destination device by SSD or USB.

You have a 64GB USB drive you want to use as the Qubes drive.

You have another USB device that has the Qubes ISO?

And the Qubes ISO is definitely starting, you’re getting a Qubes install screen?

Yes, the Qubes installation screen will appear. But I don’t see USB as a device to install to.

Just to make sure, do you have two USB disks?
One USB disk where you’ve written the installer ISO and boot installer from and another one where you want to install Qubes OS (installation destination device)?

No. I need two? Oh,It’s embarassing . Actually, I’m a beginner when it comes to technical matters.

Yes, you can’t install Qubes OS on the same disk which you use for Qubes OS installer.

Thanks. I will buy new one. And try it.