Windows 10: The boot partition is running out of space and cannot be backed up

Windows 10 LTSC 2021 version, install the system on the MBR hard drive, the installer's default boot partition, I remember is 50MB, the rest is the Windows partition. After the system is installed, when you make a system image backup, the boot partition space is insufficient, and the remaining space should be insufficient to take a snapshot of the volume. When the Windows installer is designed, it is necessary to have an independent boot partition, 50MB, is there a difference between the boot partition and the 500MB, anyway, the hard disk is to partition a small space, make a 50MB key sear

:)

 

How to go about building a tri-boot system?

i dual boot all the time, and going in to tri boot is easy.

step 1) partition the drive in to 3 partitions ( leaving 1 empty for the linux installer. )
step 2) install windows on the first 2 partitions.
step 3) install linux, and let it auto partition the remaining space. ( i recommend at least 30gb of space for linux, because it will make things a lot easier. )

step 4) enjoy.

 

Partition space

You're not understanding this. Unallocated space is NOT equal as (partitioned) empty space.

Unallocated space means empty RAW sectors on HDD. Empty space means an already allocated file system (either FAT32 or NTFS or any other) that is not occupied by any data.

So in your case, as DanTheBanjoman already suggested, don't try to shrink "unallocated space", extend the main (C*Smile partition instead. You can't shrink something that doesn't exist (unallocated space), but you can extend the existing partition over unallocated space.
So, just select the C: partition and extend it further. Program should automatically allow you to do that. I'm not using Partition Magic, but i usually done this with either:
MiniTool Partition Wizard Free - manage and resize disk partitions (also for 64bit OS!)

or

EaseUS Partition Master - manage disk partitions (only for 32bit OS!)

 

How to go about building a tri-boot system?

Yeah, but he's throwing OS X in there. Not quite as easy to do, but not all that hard. Manual configuration of GRUB is necessary.