Hello.
Any update regarding this issue ?
After setting up volumes this is what i get by launching the installer from command line :
root@solus /usr/bin # /usr/bin/python /usr/bin/os-installer-gtk
Failed to drop permissions: an integer is required
Failed to drop permissions: an integer is required
Failed to drop permissions: an integer is required

PV /dev/sda2   VG solus           lvm2 [28.28 GiB / 1.28 GiB free]
Total: 1 [28.28 GiB] / in use: 1 [28.28 GiB] / in no VG: 0 [0   ]
Reading volume groups from cache.
Found volume group "solus" using metadata type lvm2
ACTIVE            '/dev/solus/lvRoot' [20.00 GiB] inherit
ACTIVE            '/dev/solus/lvSwap' [2.00 GiB] inherit
ACTIVE            '/dev/solus/lvHome' [5.00 GiB] inherit

resize2fs 1.43.4 (31-Jan-2017)
Failed to drop permissions: an integer is required

Bye!