A lot of us seem to be having the same problem. I expect that the iCloud servers are being overloaded with everyone trying to access this new service at the same time. Think back to what happened with new iPhone activations... I'm surprised that Apple didn't plan for this sufficiently, but I expect it will get better over the next few days.
After 10 hours trying to complete iTunes Match it just hangs on Step 2 now. Made it to Step 3 with less than 40 songs to match and now this. iTunes crashes and I have to force-quit...over and over.
iTunes Match only matched 20% of my iTunes Library - all mainstream music ripped from CD's. It's trying to upload over 5,000 songs!
Cover art was perfect and now a lot is missing. Perhaps it will return if iTunes Match ever completes.
What a mess.
Again, I think it's server overload. I stopped the process and started again. Thankfully, all of the previous work remained, and I moved on to step 3. I have over 7,000 songs to upload - Lord knows how long that will take, but at least that process can be easily interrupted and resumed. In the meantime I'm going to do my best to be patient. I didn't have iTunes Match yesterday, so my life won't end if I don't have it fully in place tomorrow. It <will> work in the end, and this situation is nowhere near as dire as the transition to MobileMe was.
That's the thing...I don't need iTunes Match, but I thought it would be nice to have between my Macs, my iPhone and my iPad.
If I knew it was going to screw up my iTunes library and loose a lot of cover art I would have never turned it on.
To follow up on my earlier post...after continual hangs on iTunes Match Step 2 and then 3 (always crashing iTunes, etc.) I was finally able to get iTunes Match to complete late last night. iTunes 10.5.1 is working normally again as well.
I added two columns to my iTunes library, "iCloud Download" and "iCloud Status". iTunes > View > View Options > check both items. This allowed me to see exactly what was matched, uploaded, waiting, etc.
After reviewing all of my songs I found that there were about 40 that displayed "Waiting". No matter how many times I force-quit iTunes and tried to get iTunes Match to complete, those last songs in the wait-state would not budge. I finally deleted all of them (they were odd, non-mainstream songs and albums that I can live without plus I still have the original CD's).
Once I deleted the the "Waiting" songs iTunes Match finished instantly.
I'm not sure why those particular songs were causing trouble, but I was glad that it was finally able to finish. I eneded up missing a lot of cover art and also resolved that. More here...
So I've tested iTunes Match on my iPad, my Apple TV2, etc. and it seems to be working okay now...but what a nightmare it was to get there!. iTunes is once again behaving normally in both regular and full-screen mode. This was not a good Apple-like experience.
I too have had itunes running for days now trying to process the my library of 11,000 songs.. It has restated itself 3 times.. Once it got through step 2 but hung on step 3. I was able to listen to a few songs via my iPhone 4S, but it was very broken.. I read apple is streaming songs in 256? That is alot of data over cell networks.. Pandora has got there act together... If it runs into data bottlenecks it reduces the bit rate and sends less data as not to compromise the buffer stream... I just want to be able to listen to my library wherever I am... not attached to having the "Hi-Fidelity, 7:1, Dolby THX" experience when I am driving my car or on a wal with my dog or whatever. For now I have stopped the match process... maybe in a week or so I will try again.. For now, reliability is more important and I am sticking with Pandora... ROCK ON WORLD!