install windows 10 system reserve problem

[magi]

I installed win 10 on a sata 500gb hdd partitioned to 150GB for windows and the rest unallocated. Then installed ubuntu on a SSD 120Gb drive. No problems. Both booted up fine. Then intermittent power surges and cuts trashed win10.

I then re-installed win 10 in the same 150GB partition on the sata hdd while Ubuntu continued existing on the SSD drive

A message during the win 10 installation demanded a partition for system reserve. Thinking this was for the boot files I made a 500mb partition in front of the OS system partition. Win.10 did not install anything into this partition. It was left as free space. Windows has not created any other partitions on the sata drive But this free space has caused big problems for ubuntu because although Ubuntu can still boot windows it can boot in read only as it does not know what the "free space" is so considers it to be active (busy) in some way.

I am going to re-install windows again.
Question: Does the windows operating system partition contain the boot files so no need for a separate partition.
During the previous installation was the demand for system reserve space referring to a type of recovery partition that can be created anywhere on the disk.
Considering the free space partition was only 500mb It seems odd that widows accepted it as enough space for a system reserve/recovery partition.

Am I a complete idiot reading this situation completely wrong. Any explanation to clear this confusion would be gratefully received. I do not want to have to re-install windows for the 4th time

Thanks

 

[chrunos]

if you have partition your hard drive before starting to install Windows, then Windows will not require a system reserved partition. in your case, you install Windows on the 150GB partition created before, so Windows will not need for a separate partition. if you select unallocated space to install Windows, then it will create a 500MB system reserved partition. You can merge the free space to one of your existing partitions with free third party software, such as AOMEI Partition Assistant.