Disaster! Sort of.
After receiving only one response by jglen490 (Thanks!) to my post, decided to strike out my own. Tried to experiment to see if I can solve it on my own. Mixed results.
This is a retrace of my steps.
Booted my laptop, plugged in my hybrid install external SSD into a USB port. I could see all files and etc on it. Opened gparted, laptop showed up as sda, external drive as sdb. Unmounted sdb.
On the external SSD, using gparted, shrank the, /, partition to about 75GiB, just a little over its current used size. Made a new partition, /home, using the remaining free space. Screen shot of what I ended up with.
Shut down. Booted external drive. So far so good! No problems. Feeling pretty cocky by my repartitioning success, decided to copy and paste home folder from /home to the new /home partition. Worked, all files were there.
This is where things started to go haywire!
Believing that the home folder in the / partition isn't necessary any more, deleted it. Rebooted the external drive. It booted to the grub rescue> screen.
The first big, OOPS!!!, what have I done?
Shut down, unplugged the external drive, rebooted laptop, no problems. Plugged in external drive, opened gparted. Laptop partitions on sda, good, same as before. The sdb3 the / partition used space a bit smaller, the sdb4 the /home partition was larger by the about same amount.
After mulling it over for a while, decided to use Mint install to fix things up. Thinking it will fix the grub problem. Booted up with Mint ISO USB, started install, chose Something Else. The external drive was now sdc. Kept the same partitions, with no format on sdc1 and sdc4. Trying to keep the grub2 core.img and home partitions intact. Clicked install. I might have ignored a warning and continued.
An error message appeared saying "install cannot be completed" or something similar, not sure of the exact wording.
Shut down. Unplugged USBs. Rebooted. A blue screen of Dell repair memory test opened. Shut down, not much else I could do. Hoping that I didn't totally bork my machine (a lot of $ down the drain) rebooted with a Mint ISO USB.
It booted up! Opened gparted. Lo and Behold an sda drive with 1TB of free space! Shut down.
Had a two fingers of scotch with some ice and a splash of bubbly water and called it a night.
The next step was to do a clean install using the Something Else option, partitioning for / and /home partitions.
Reloaded my applications, restored my data files and etc.
Now my laptop is set up that way. Not the way I first intended by using my external drive as a test bed and apply what I learned to my laptop. Meanwhile my external SSD is still borked. I'll reinstall Mint 19.1 on it using pbears viewtopic.php?f=42&t=287353Hybrid
Method again using Something Else option.
Made some mistakes, one of which maybe to unflag my sda drive, as mentioned in pbears post.
A note to self! Timeshift isn't any good if its on the same drive that is borked! Save it to an external drive!
All in all I consider this a good learning experience. Didn't lose any data, I use my desktop for the important stuff.
I hope that someone else doesn't make the same mistakes that I did after reading this post.
My other thought is that the first option in Mint install (Erase Everything) should be to set up to create / and /home partitions automatically. A new user would never be aware of the difference between and the current set up. It may make it easier to solve problems later on.
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If you found a solution on your own please post it.