Installer does not recognize previously installed system

[Eugenia T]

Context:

Step 6 in "Install (auto-resize) in Ubuntu Desktop amd64" in Hirsute Final (version 20210420).
Configuration: VirtualBox 6.1.18, 3GB RAM, 20GB vSSD, host CPU: Intel i7-4510U

Actual results:

Intermittently (I could not determine any specific dependency) step 5 "Click on the continue button" on the screen "Updates and other software" is done but step "Select Install Ubuntu XX.XX alongside SYSTEM YY" is not available - the installer thinks there's no system installed yet. Screenshot (3.jpg) is attached.

Expected results:

After clicking on the Continue button on the screen "Updates and other software" step "Select Install Ubuntu XX.XX alongside SYSTEM YY" is available.

[Ubuntu QA Website (ubuntuqa)]

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:
http://iso.qa.ubuntu.com/qatracker/reports/bugs/1925219

[Sai Vinoba (saivinob)]

@sov-j, Can you confirm what was filesystem of the previous install? Was it a ZFS install or an encrypted partition?

I can confirm the installer does not recognize previous install if it is,
1) an encrypted partition
2) a ZFS partition

I did not face this issue when the previous install was on ext4. The installer showed 'install alongside' option correctly.

[Sai Vinoba (saivinob)]

The installer also does not recognize previous LVM partitions.

Did two tests:
1)
a) Let first flavor do 'Entire disk' install with LVM selected.
b) When installation completes, reboot with second flavor iso.
c) Installer does not recognize the first install's LVM partitions and hence does not offer to resize or install alongside.
d) Choose 'Something else', we can see LVM partitions which can be re-used (overwritten) to complete installation.

2)
a) Booted with first flavor, create LVM partitions but only on half of total disk size (e.g., 15G of 30G).
b) Choose 'Something else', we can see lvm partitions, complete installation.
c) When installation completes, reboot with second flavor iso.
d) Installer does not recognize the first install's (manually created) LVM partitions nor the free disk available and does not offer to resize or install alongside.
e) Choose 'Something else', we can see the LVM partitions and the free space, choosing either of them (i.e., either overwrite on LVM or install on free space to get dual boot), we can proceed with installation.

So, the install side-by-side (auto-resize) does not work with previous,
a) encrypted partition
b) ZFS partition
c) LVM partition

[Eugenia T (sov-j)]

I also can confirm that the installer does not recognize previous LVM partitions, encrypted partition and ZFS partition.