Windows 10 installer doesn't create all additional partitions

I installed Windows 10 on a new 500GB SSD (Sabrent Rocket 4 Plus), and the installation process finished successfully, but now a problem came up. Windows Update fails installing updates with error code 0x800f0922, which means there's less than 500MB free space on system reserved partition (Windows Update Error 0x800f0922).

In the installer, when I needed to select the drive to install Windows to, I created a new partition from the whole free space on the SSD (It was completely empty, without any partition). The installer said that additional partitions will be created too, which I know from previous installations. However, this time only the 15MB-sized MSR partition was created in addition to the one constructed from the remaining available free space (Windows partition, containing the OS).

I also have a 2TB HDD with a Windows installation on it, the additional partitions exist on it.

There's no system reserved partition on the SSD bigger than 500MB in size, and I think this is the cause of the failing updates.

How to fix this problem?

If you created a partition over the whole disk, Windows was unable to create the MSR in the little space that was left unallocated.

The easiest for you might be to delete this partition and repeat the install, giving it this time the whole unallocated disk to use. It will create all the necessary partitions and use the rest of the disk (almost all) as the C: system partition.