Insect identification- FL

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ibb.co/BVbRjHK
ibb.co/gg4MLK9

I see these insects at our office around desks/computers. When I worked from home for a bit, I started seeing them near my home computer. I did bring file folders home. Once I moved everything back to the office, I stopped seeing them at home. Any ideas? No plants at home or at the office.

[livingplanet3]

Those are phorid flies (scuttle flies) -

bugguide.net/node/view/14163

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What are they attracted to? No plants or food at either office. I’ve stopped seeing them at home now that I moved back to our office. Is it possible it’s the file folders?