Question Windows 10 Boot Issue

[Palador]

Hi, everyone.
I've been running Windows 10 on my Crucial MX500 for a while now, but recently did some hardware upgrades (Ryzen 3 1200 to Ryzen 5 3500X, 2 x 4 GB RAM to 2 x 8 GB, etc.). I also got a new Silicon Power UD90 PCIe SSD that I wanted to use as my primary Windows installation and use the MX500 for testing software, etc.
I installed Windows 10 on the UD90, but then decided I may as well install Windows 11 instead, so I did that.
I didn't have a problem booting from either drive and I used the Windows 10 installation on the MX500 extensively last night after installing Windows 11 on the other drive. This morning, however, Windows 10 on the MX500 won't boot.
Windows 11 on the UD90 boots without issues, but when booted in Windows 11, the boot drive on the MX500 appears as an inaccessible NTFS drive with 0 bytes used and 0 bytes available.
When I opened Disk Management, all the partitions appear healthy and fine. If I check the properties of the boot drive on the MX500 there, it shows the proper amount of GB used and free (about 240 GB each).
When I inserted my Windows 10 USB installation disk and ran Notepad.exe all my files and folders were visible in the MX500 boot disk, so I know everything is there, but how can I get it to boot properly?
It would seem like there should be a simple solution, but it's not really coming to me. I appreciate any advice.

Current Build:
MSI B450M PRO VDH
Ryzen 5 3500X
XFX Radeon RX 550 (4GB)
2 x 8 GB G.Skill Aegis DDR4 RAM 3200 MHz
Crucial MX500 2.5" SSD (500GB)
Silicon Power UD90 PCIe SSD (1TB)

 

[hussaj]

So you installed WIN 11 then WIN 10?
If that it is, you should have done the opposite

 

[Palador]

So you installed WIN 11 then WIN 10?
If that it is, you should have done the opposite

I'm not sure how you got that impression.
No. I have Windows 10 installed on my old drive.
I then installed Windows 10 on the new drive and updated it to Windows 11 with an ISO.
So I had Windows 11 running on the new drive and Windows 10 on the old.
Now Windows 10 on the old drive doesn't boot.
When I boot into Windows 11, the Windows 10 drive looks like this in File Explorer:

In Disk Management, it looks like this:

And when I open Notepad from CMD, then the files and folders appear normally: