As of March 2014, The "import customers from CSV file" feature built into Service Desk is currently not able to update customers (it only creates them). i.e. If the customer already exists, then that customer is skipped over.
I created a Windows program that updates the customer if they exist and if they don't exist, then it creates the customer.
DISCLAIMER: Like most programs I make, you cannot get official technical support from Citrix tech support department, but, I will try to help you (as time allows).
DOWNLOAD HERE:
https://citrix.sharefile.com/d/s82e61... It's a self extracting EXE file so just put it in a folder and run it.
