Can't access some folders, despite service running as system user

[ts678]

Welcome to the forum @Nyechm

@Nyechm

I create a folder that only the admin has access to

If you mean that it lacks SYSTEM, there’s the cause:

C:\backup source>whoami
nt authority\system

C:\backup source>type only_for_me.txt
Access is denied.

Unlike root on many UNIX systems, SYSTEM still needs to be granted access, or it has no access.