Q: Sync Session Failed to Start iTouch iOS5

I just unticked the"sync over wifi" and then it all worked fine. I hope this helps

Same issue happened after I updated to iOS 10.5.2.  Ipod also on latest update.  Windows 7.  I followed the suggestions above and got nowhere until I checked sync with wifi, closed itunes, opened itunes unchecked all sync options, closed itunes, opened itunes, plugged my ipod touch into a power supply other than my pc, then went to file>sync (my) iPod.  Now it is syncing again.  Why it is still able to sync after I unchecked sync with wifi, I have no idea, but it worked.  It didn't work until I plugged the ipod into a power supply, even though I have a full battery. 

Thanks for making it so simple, Apple!

This helped me. I realized that my iPod Touch was plugged into a USB hub that didn't have the power supply connected. Once I plugged the AC adapter back into the hub, and plugged it into the wall, the iPod suddenly started syncing.

This really helped i suggest it

This is ridiculous!  I have searched all over, found a ton of hacks of restarting iTunes, syncing over wi-fi, deleting your iPod photo gallery...  NONE of them has worked for me.  I'm about to throw my Mac and my iPhone out the window!  APPLE, please help!  This was fine until I downloaded the latest version of iTunes.  Now I can't even revert to the older version of iTunes either...

i had the same problem so i read through this thread. i tried most all of these and they did nothing on their own until i ...
1) unplugged my itouch from the pc's usb port and plugged it directly to the walls a/c power and
2) restarted my pc

i then restarted my pc and reconnect via the usb port.

so i would try 1 & 2 first since it's the quickest route and it was then i actually saw any type of result.

however prior to that ....
did a restore of my itouch software - which took a while to download
turned wifi sync on/off
did the reset warnings option
checked for updates to my itouch
downloaded the latest version of itunes

all to no avail until i finally did 1 & 2

not sure what the combination was but i'm up and running again

Had same problem with my iphone. Make sure someone didn't log you out of the Istore and log themselves in. Not sure why but once I logged back in sync worked just fine.

Unplugging my iPod Touch 4G, then plugging it into a wall outlet, while restarting the computer and replugging my iPod back into the Computer once the computer restarted worked. Thanks!

I also had this problem, and had no luck with any of the suggestions in this thread until i came across the  plugging into another power source and restarting the computer theory. thankfully it worked a treat! i recommend everyone try it before restoring their ipod or making any other dramatic decisions.

I have the very same problem and absolutely nothing has worked!  I'm so frustrated!!!  Did you ever get your Mac/iPod Touch sync problem resolved?

This answer listed below just fixed me up.

This was happening to me.  I found on another thread that if you power cycle your ipod (or iphone), by simultaneously holding down the home and power buttons, and then try syncing it again it should work.  I tried this and it worked for me.

I found that what Phil Weyman said with the sync wirelessly worked try that.

I tried everything but just after rebooting both imac and ipod touch I was able to sync.

uffff

The power cycle worked for me.

Try turning off wifi. I just did it and now I'm getting my movie transferred =)