Imapsync is very useful migration tool, however it has some undocumented limitations that you have to discover, isolate and work around.
I had problems using imapsync with certain characers in folder and password fields. Specifically, it didn't want to work with spaces or special characters in folder names, plus it didn't like periods or certain special characters in passwords. It also doesn't like very long folder names or deeply nested folder sets.
The program moved most of my users and folders find after a bit to testing. I examined the output logs and manually ran imapsync on troublesome accounts and folders. [In my case, this was easier and faster than trying to fix the underlying program limitiations.]
For me, the solution was to change all folder names to alphameric only, change passwords as well. Still ended up with a few folders that I had to copy over by hand using Thunderbird.
Macy Hallock - Hallock Consulting - Medina, Ohio