What to do if you need to roll back \ undo your virtualized client
Use the Force - To get the server and workspace versions in sync again perform a get using the force option.
If you are using Hyper-V a better solution is to put your workspace on a drive that is offline to the host OS (Windows 2008) but known to the Hyper-V machine. You have to disassociate this offline drive from the Hyper-V machine before you do the rollback and re-attach afterwards. This keeps the rollback from affecting the workspace drive, leaving your workspace files the same.