The safest way to backup your presets for the BIAS series software, is to backup the following folders:
BIAS FX 2:
Documents/PositiveGrid/BIAS_FX2
BIAS Amp 2:
Documents/PositiveGrid/BIAS_Amp2
BIAS Pedal:
Documents/BIAS_Pedal
BIAS FX 1 (Discontinued):
Documents/BIAS_FX
BIAS Amp (Discontinued):
Documents/BIAS_Amp
To restore the presets, simply paste the backed-up preset folders (as listed above) to the same exact directory on the (new) computer.
For BIAS FX 2, an alternative way for backup would be to utilize Cloud Banks, which automatically sync your presets (that are saved in Cloud Banks) across devices, as long as internet connection is available and your same PG account is logged in. Please refer to this article for further details on Cloud Banks.