It sounds like it might be a ridiculous, crank question right, but the answer will surprise you. Dr. Peter tells us: “Believe it or not, they get lighter. USB drives use Flash memory, which means that the ones and zeros of your data are stored on transistors. When you save data, a binary zero is set by charging the float gate of the transistor, and a binary one is set by removing the charge.
To charge it, we add electrons, and the mass of each electron is 0.00000000000000000000000000091 grams. This means that an empty USB drive (which mostly holds zeros) weighs more than a full USB drive (which has ones and zeros).”
Still with us? Mind officially blown.
Before you get your scales out however, he also tells us that you would need to weigh more USB drives than currently exist on Earth at the same time before you could easily measure the difference. Still. Cool fact for a lockdown weekend.