I was seeing this on one of our servers, I looked at the Services running and ran profiler and came up with the same things like: generic queries where NT AUTHORITY\SYSTEM was trying to run things like:

SELECT size / 128.0 as fileSize,

FILEPROPERTY(name, 'SpaceUsed') / 128.0 as fileUsed,

CASE WHEN max_size = -1 OR max_size = 268435456 THEN -1 ELSE max_size / 128 END as fileMaxSize,

CASE WHEN growth = 0 THEN 0 ELSE 1 END as IsAutoGrow,

is_percent_growth as isPercentGrowth,

growth as fileGrowth,

physical_name

FROM sys.master_files WITH (NOLOCK)

WHERE type = 0 AND is_read_only = 0 AND data_space_id = 1

AND database_id = 4

Turns out System Center Operations Manager Agent was running HealthService.exe as Local System.