iTunes was unable to load provider data from Sync Services.

Hi, i was hoping you could help me - ive tried the two fixes in this thread - first copying the files over and restart same error message - then deleting the back up files - which i saved a copy of to my docs in case and still getting the error message.... can anyone help me??

I have also tried everything, the deletion of the back files worked like twice, the copy paste files did not work at all.

I am still locking up and non-sync.

What now?

Even went to Apple store and they reloaded but once again, maybe three sync and everything locks up.

I have also been having this problem. I get the error message and then it proceeds to act as though it is backing up and syncing but nothing truly happens.
I tried the delete files method mentioned earlier.
I tried the copy files method mentioned earlier.
I uninstalled and reinstalled itunes.
Still having the same issue.
I'm on iphone 3G with Windows XP and iTunes 9.1.1.
If anyone has any additional ideas, I would love to hear them as I have been unable to sync for a couple weeks now.

Have been thinking about copying my itunes files to my laptop (Windows 7) and syncing with that. Any thoughts?

I copied itunes folder to laptop (Windows 7) and was able to sync. So issue would appear to be specific to pre-Windows 7 OS.

It didn't work for me either but I found another solution for syncing contacts and calendar from MS Outlook 2007 with my iPhone 3gs and it can be done wirelessly! If you don't have a Gmail account get it now. Once you have that set up do two things. First, in Outlook click on File > import and export > export to a file > comma separated values (Windows) > select "contacts". Give the file a name that you will remember and save this file to documents. You can do the same for your calendar. Then go to www.google.com/mobile/sync. Click "Read setup instructions" under iPhone and follow the instructions on that page. I did this just last night and miraculously all my contacts and my calendar appeared on my iPhone. My frustration level has abated!

Nice work-around, but no solution. I just want to synchronize with USB on my PC, with outlook 2007, just as it shoulde be......

I have tried settings above, deleting backup, copying files, reinstall iTunes, downgrade to an older version / reinstall PC.... but still the annoying message and worse..... no sync with Outlook Calendar.

Anyone, anyhow, anywhere......???