Issue:

User can’t connect to XenDesktop, the session launches initially but stops at “Preparing your desktop” and then closes without any errors.

Event log errors on XenDesktop controllers:

No connection license available. To resolve, free licenses by closing sessions that are not needed, or add more licenses. Details: 
License Server Address: ‘LicenseServer.domain.local’ 
License Server Port: ‘27000’ 
Desktop ID: ‘CD8A4005’ 
User: ‘Domain\Username’ 
Client ID: ‘6F713A64’ 
Desktop Kind: ‘Shared’

Citrix Desktop Studio – Licensing:

If you’re scratching your head at this point thinking there’s no way you are using more licenses than you have the most likely cause is that Citrix Licensing Server allocated a few licenses to devices instead of users.

Citrix licensing server has a complicated algorithm for working out which type of license is going to work best for each session and allocates the license accordingly. Unfortunately this doesn’t always that well.

To check how you’re licenses are allocated logon to your license server, open command prompt and run

C:\Program Files (x86)\Citrix\Licensing\LS>udamin.exe –list

This will display all currently allocate licenses and look something like this:

As you can see there are 8 licenses allocated to devices which we need to delete using:

C:\Program Files (x86)\Citrix\Licensing\LS>udamin.exe –f XDT_PLT_UD –device 255C42F8 -delete

Just repeat this for each device name in the list and your license allocation should be back to normal.