I agree that you should be able to backup the 1st partition to the second (verified on my system). I don't see anything obviously wrong in your screenshot of Disk Management.
Just a shot in the dark but you could try opening a command prompt and entering "sfc /scannow" (no quotes) to check your system files.
My Computer
Computer type
PC/Desktop
Computer Manufacturer/Model Number
Home Built desktop, Dell G15 5511 Gaming laptop,MS Surface Pro 7 tablet
OS
W10 Pro desktop, W11 laptop, W11 Pro tablet (all 64-bit)
CPU
3.7Ghz 8700K i7, i7-11800H, i7-1065G7
Motherboard
ASUS TUF Z370-Pro Gaming in desktop
Memory
16G desktop, 16G laptop, 4G tablet
Graphics Card(s)
AMD Radeon RX580, RTX 3060, Intel Iris Plus
Sound Card
High Definition Audio (Built-in to mobo)
Monitor(s) Displays
Samsung U32J59 32" (2x), 15.6", 12"
Screen Resolution
3840x2160, 3840x2160, 1920x1080, 2160x1440
Hard Drives
500G SSD for OS; 2T, 10T & 15T HDDs for Data on Desktop, 1TB SSD laptop, 128G SSD tablet.
PSU
Corsair CX 750M
Case
Antec 100
Cooling
CM 212+
Keyboard
IBM Model M - used continuously since 1986
Mouse
Microsoft Pro IntelliMouse
Internet Speed
400M down 8M up
Antivirus
Windows Defender
Browser
FireFox
Other Info
Built my first computer (8Mhz 8088cpu, 640K RAM, 20MB HDD, 2 360K floppy drives) in 1985 and have been building them for myself, relatives and friends ever since.
As an addition to that advice..... Use macrium reflect FREE of AOMEI Backupper (also free). They can restore some partitions from the backup instead of all. And they can resize partition on restore.... so can restore to smaller disk, or to disk with other partition layout.
My Computer
Computer type
Laptop
Computer Manufacturer/Model Number
ACER ASPIRE 5742G
OS
Microsoft Windows 7 Home Premium 64-bits 7601 Multiprocessor Free Service Pack 1
CPU
Intel(R) Core(TM) i3 CPU M 370 @ 2.40GHz
Motherboard
Acer Aspire 5742G
Memory
4,00 GB
Graphics Card(s)
ATI Mobility Radeon HD 5400 Series
Sound Card
(1) AMD High Definition Audio Device (2) Realtek High Defi