Does computer weight increase as I add data to my Hard disk? [duplicate]

Solution 1:

Special Relativity tells us that energy has mass. Therefore, the kinetic energy of the spinning disk platters will cause your HDD to gain mass when you switch it on.

This is probably more significant than any mass change you may have from the data stored.

Of course, the mass gain is still infinitesimally small.

Also, to be really pedantic, weight is the manifestation of mass in a gravitational field. So, the weight will change if you carry the disk upstairs but the mass won't.

Solution 2:

As Wikipedia says

An HDD records data by magnetizing a thin film of ferromagnetic material on a disk.

Magnetizing material only changes the polarity/direction of the material's inner parts, it does not add or remove material.