Sam Steti wrote:No, I think HFS+ could have been a choice at installation time, for example if your OS was still HFS+ when you installed Mojave meaning you may have kept Mojave on HFS+). APFS+ obligation came on subsequent OS versions...
Anyway this is no longer your worries, obviously. Personally I'd install a fresh OS on an external disk and boot on it for tests purposes...
when installing or updating to mojave, HFS+ is automatically converted to APFS.
which is the worst method, because the FSroot tree is damaged, which even the apple disk utility
can not repair (not even in recovery mode).
with mojave you could keep the HFS+ format by restoring a clone, but after that no updates worked.
since catalina this does not work anymore.
has unfortunately nothing to do with the problem of the TS, because with his configuration
the startupdevice is on APFS anyway.
I would in his place once the eltrecheck software check whether a conflict with extensions is present.