Just to reiterate.
You must book an LH flight with the LH flight number (not a UA code share flight number).
You must book in Y, B, M or H.
You must have a paper mileage cert from UA.
You must call UA international reservations once a week and ask them to send a message to LH requesting the upgrade, because LH does not maintain a waitlist.
During the last week before the flight, you must make this call to UA every day.
You must not expect the upgrade to clear until a day or two before the flight.

Thank you! I appreciate the advice. (I'm a newbie at this [Lufthansa travel])

Or C. ;)

How does one find I or O inventory on LH? As far as I can tell, they're not listed on SeatCounter...

I don't know. It used to show sometimes on ExpertFlyer, but now, no.

The folks at the LH ticket counter will tell if you ask them about a specific flight.

Any idea if they'll tell you if call reservations?

Never tried.

Some UA agents will tell you if there is "I" or "O" inventory, but they will tell you that there is no gaurantee that LH will honor an upgrade request just because the inventory is available. :rolleyes:

I personally have had a 100% success rate with confirmed upgrades on LH if there was I or O inventory available when I requested the upgrade.

The way that I can find out is by using LH's own mileage redemption booking tool. If the seat is available for a mileage redemption, it's also available for an upgrade.

The caveat:

- you need to be a Miles&More member
- you need to have enough miles to actually be able to redeem the award you want to check

Thankfully, I have quite a number of LH miles in the bank (and the account number and PIN of my father's M&M account, for the few times that my own miles would not be enough for something I want to check... :D ).

(Bolding mine) I think that LH may actually maintain a waitlist, they just won't put UA requests on it. My reason for this thinking is that I have an LH flight next week FRA-DEN and my TA has access to LH systems. She went in and requested I class for me (just playing around, really) and the system took it. I still shows several days later as requested. I have no idea what will happen if they decide to give it to me. They may pull miles or expect a cert next week (I have a SWU printed for LH that I was planning on trying to use). Of course, the flight is pretty much sold out (0-3 seats avaialable any given time I check) so I'm not holding my breath.

Sort of corrected. My statement was with the understanding that UA has cancelled their members' ability to use the *A upgrade system.