It appears Wiz that sdb partition is Serena??
Nope, it is /dev/sda. I'll tell you why.
1. Your background wallpaper is called "Valley", which is from LM 18.2 'Sonya' - not available to Serena but available to Sylvia.
2. On the GParted shot there, under Mount Point is a / which indicates your root partition on that drive, and as you are following my instructions and taking these from Sylvia, that forward slash shows you this is Sylvia.
So first screenshot is Sylvia. /dev/sdb1.
Second screenshot is Serena - the problem child.
You have all the space in the world on /dev/sda6 which is your root partition for Sylvia, and by the looks of it includes Home, which is likely consuming the most space.
The immediate problem is Boot, on /dev/sda1.
This is a legacy of the gooses (geese?) whom you refer to as Techies from the computer store in the big smoke.
/dev/sda1 is only 7.45 GiB to start with, and something is crowding up 6.8 Gig of that, leaving 660.43
MiB - but a couple of hundred of those are used as formatting overhead for establishing and maintaining the partition.
Hence your warning of only 193 MiB left. Linux starts to choke, when space has run out on Boot.
The Techies also did a good number on us, by making the Extended Partition /dev/sda2, instead of at least /dev/sda3 and preferably /dev/sda4.
As it is set up currently, there is no way to "grow" /dev/sda1 to eliminate the error message and have a working Serena, unless you first delete -
- /dev/sda6 and then
- /dev/sda5 and finally
- /dev/sda2, the Extended Partition
... and in doing so, you are deleting Serena.
You may be happy to do that, or you may wish to keep the 2nd System (handy sometimes).
So digest a bit of what I have said, think about your options, ask questions.
Keeping Serena and fixing it is not out of the equation, because
- There's more than one way to skin a cat
- Where there's a Will (or a Dick and Chris) there's a way, and
- Wizard ain't easy to beat where multibooting is concerned
I'll grab coffee and attend to some matters and be back in the fullness of time.
Wiz