I have tried numerous times to use the miles that have accumulated on my Lufthansa Miles and More card (about 100,000) and each time its a different excuse why the reward flight or the upgrade won't go through:
I tried it with the Star Alliance member Mexicana and it was "you can only accrue miles with this partner, but you can't use them" (after I had booked the flight)
Before booking the next flight with SIA I called Miles and More to verify that I would be able to use my miles for an upgrade. After booking the flight I tried to get the upgrade and it was "sorry, it did not go through, all the upgrades are gone"
I called Singapore Airlines and the answer was: "Star Alliance members can only accrue miles on our flights but they are not eligible for upgrades"
This information was different than the information on Lufthansa's website that lists SIA explicitly as a partner on which a Miles and More cardholder can get an upgrade. I wrote a letter to SIA asking them to give it to me in writing that Star Alliance members are not eligible for upgrades but after more than a month I have not received a response. They would not answer my emails either.
After submitting my boarding passes to Miles and More a note was put into my account: "This booking class (Y) does not accrue miles"
Miles and More does not mention anywhere that they honor certain flights with their Star Alliance partner with zero miles. Actually I could have chosen a flight with about 15 hours less flighttime/ layovers for about 1/2 the price using Hawaiian Airlines. The only reason I decided to use SIA (with over 12 hours layover in Singapore) was the option of getting an upgrade.
Miles and More and SIA pissed me off completely, if they believe that this is a way to gain the customers loyalty they are wrong and I hope that I am not the only one.