I forgot my passphrase for unlocking my disk. Is there a way to disable it and reset? I've tried using software from a USB drive but won't recognize it. Please help
If you have full-disk-encryption enabled, there's no way to bypass it. That's why it exists.
Your only recourse would be to wipe your drive and try to reinstall Ubuntu.
To erase your drive, open
gparted on live media and select the disk you installed Ubuntu on. Navigate to Device > Create Partition Table. If you have a UEFI-aware computer, select
gpt and confirm. Otherwise, select
Once your drive is cleaned out, you can customize the partitions for it, or just install Ubuntu normally.