Partitioning – Upgrade to 18.04 with Password Protected Hard Disk

In August 2018, I was allowed to upgrade from 16:04 to 18:04 on my computer. Everything seemed to work well until I logged out and tried to log in to my system again. I poked around, trying to find answers to my reasonable questions. In the end, I created a live CD for Ubuntu 18.04LTS Desktop to reinstall the 18.04LTS system. I found the instructions on the website I reached step 6. Select the appropriate installation type and draw a blank. The hard disk on which 16.04LTS was installed is a password-protected hard disk. When booting the Live CD, I was able to access the drive by typing the password and see all my files. I could see the partitions as Ext3 / Ext4. However, if I chose something else in step 6 of the installation and I wanted to continue without formatting because the format was already formatted, the installation process could not see the partitions because the disk is password protected. There is no way to enter the password and to notify the installation of the existing partitions. It just believes that there are no partitions. The only way to install it is to repartition the already partitioned disk. When I partition the hard drive, I am prompted to enter the password (for the hard drive). Thereafter, the existing partitions are overwritten. Even though I've saved a lot of the content with Live CD, I do not want to risk losing all my files if that can be avoided.

How do I get the 18.04LTS desktop install process to force hard drive access (requires the password) BEFORE verifying partitioning on my password protected drive?