Why is my hard drive space disappearing while I do nothing

[johnrohn]

When I hit "Get Info" on my hard drive in Finder, my used space just keeps ticking up. Why? What is using this space? It happens whether my wifi is on or off. My Time Machine is turned off.

 

[lcubed]

when you run the activities monitor, under the CPU tab, what programs are running?

other details like machine type and what OS is being run may provide some context for diagnosis

 

[HDFan]

Disk space usage by the OS is constantly changing. Caches, memory swapping if low of memory, backup snapshots, application temporary files, etc. You can use programs such as Daisy Disk to see where you disk space is going.