Scan fails with incorrect "no space left" message

Today when I try to scan a document using DTPO, I get an error telling me “the file couldn’t be saved because there isn’t enough space. Remove some files from the volume, and then try again.”

But I have 1.45TB of space left.

It happens when choosing a “scans” folder or an inbox destination.

Hm… I seem to have rectified it by typing the resolution into the drop-down menu. Not sure why it came up with the error, because “300” (dpi) was entered before.