What does message "iTunes was unable to load data class information from Sync Services. Reconnect or try again later." mean?

for what its worth- I haven't updated itunes for a while (ie its not the latest version) but have had various auto upgrades on a work laptop (windows) since the last time I tried to backup the iphone - so I guess that's where the problem lies?

Boosting this in the hope Apple relaese an update or something- this occured on both updated and non-updated itunes. Been searching for about an hour and nothing suggested is working for me.

Agree - Apple need to jump on this very quickly. Currently having "salt rubbed into wounds" - my Co-Director currently using his Samsung Phone and Tablet to Sync seamlessly.

Ok, so I've just spent 1hr 40 mins on the phone to Apple, they tried everything, uninstalling itunes shutting down, reinstalling, uninstalling antivirus plus various others things and it's still not working, they think it's my PC, but I'm not totally convinced. It's been sent over to an engineer so I'm hoping I'll hear something tomorrow. Fingers x

Nice One Jack - I'm with you - I'm not convinced it's the PC's of all the people currently experiencing this problem.

Fingers X the Engineers find a solution and not an excuse.

Thank you- I tried to do the same but was stuck in a queue for twenty minutes

Fingers crossed

My Win 8.1 started to do this today and PC became very sluggish

Fixed by removing iTunes et al and re-installing ,message now gone away and PC now working at normal speed

There is some recommendations that "WE " should all remove the 16/8/ 2014 Microsoft update, appearing in online PC journals .

Plan to find out if MS are also saying same

Very much doubt this is an Apple issue ,no Apple updates recently and with the comments about MS.............................

Update just started coming up again ....curses

Was just about to post to say above didn't work for me again... contemplating reverting to a restore point, but not sure this would help any. Thoughts?

I also have this problem. Happened today after upgrade of iTunes. No issues in the past few weeks, just started now.

Would like to see a resolution. Nothing on my PC has changed except the iTunes update.

Looking like this could be all down to August hotfixes rolled out by Microsoft... http://www.pcworld.com/article/2465631/microsoft-pulls-august-windows-update-aft er-crashes.html, I'm just trying the uninstall of all hotfixes from MS applied since August 16th (was on vacation before then) and see how things go from there...

I have had this problem today as well.

I sync every day. It worked yesterday but as of first thing this morning I got the error.

My wife's machine is doing the same as if my farther's at the other end of the UK.

There is clearly something wrong which we, as users, can do nothing about.

I run NOD32 anti virus but tried disabling that before trying my wife's machine.

There have not been any Microsoft updates today that i'm aware of.

Sadly, uninstallation of the MS hotfixes, on Windows 7, hasn't resolved the issue.

Time for the iTunes/MS support teams to earn their money and come up with a fix.

Mine has started doing this today after an iTunes update...