A few weeks ago I had the dreaded "roof operation not complete" message coming up when the roof was up and I was driving around.I noticed that one corner of the roof at the rear was slightly popping up-about 1cm off the body. This was enough to make the computer think the roof was opening. To cut a long story short, the fault was due to the gas struts that hold the roof taught against the body when up. There are 2 struts on each side,with two different forces. I ordered new ones -not from Alfa, and with a bit of help replaced them all for about £60. When the old ones were off I could easily push the struts in by hand as opposed to the new ones which were much harder. After driving around now for about 3 weeks with no error messages,I am pretty confident the fault has gone.