Hi guys, I hope somebody can help me.

I've recently attended a CITRIX course and have been tasked for setting up my companies new CITRIX servers. Everything has been going fine, until recently, and I can't find a fix anywhere. Completely at random, when users click on an icon, the client starts, and you receive the logon screen but the application itself doesn't appear. This doesn't just happen with one application, such as Microsoft Word, it happens to any application.
Whats frustrating, is that there's nothing in the event log and there are no error messages. In CITRIX Management Console, it shows the user is connected. Also this doesn't happen with just one user, it happens with any new user that tries to connect, and I have to reboot the server to clear this problem.

Hi flipflopUK, welcome to PCHF.

CITRIX relies on two major services, the IMA service and believe it or not, the Print Spooler. The IMA service is obvoisly working becuase you can make the initial connection. Next time this happens, go to Printers and see if you can see the list of printers here. If it freezes at this point, it's a good chance your Print spooler has failed. Go to Administrative Tools, Services and restart your Print Spooler, and your application should appear. Look at your published application, you will probably see that it's set to create a client printer before starting the application. If there is a problem with the print spooler, it won't be able to do this, therefore the application won't start!

OMG monkey, you are amazing, the print spooler was the problem.
Do you know what would cause these failures?

Hi Flip,

Yes, it's normally caused by the print driver itself, particularly with the newer HP drivers.

For example with the HP 1300 series printer, if two users try to print using the same print driver at the same time, this will cause a spooler failure. If you give me a list of your printers, I can tell you if there are any problems with them and suggest any alternatives.

That would make sense, since I didn't start having these problems until the last 10 or so users were added, and they do have the same printer drivers.
We have 9 x HP Laserjet 1320's
4 Dell 3120cn's
2 HP Deskjet 5550c's
we do intend to add more, but these are our current printers we have on-site.

The 1320's have the same problem I mentioned before. Most laser printers, including Dell print quite happily using the HP Laserjet 4 plus or 4si drivers (if you have printers with duplexing units).

The Dell 3120's don't have any problems at all working through CITRIX.

The Deskjets are a bit of a problem, as there are no real alternatives, except that when you buy a new deskjet, try to buy a different one each time.

One more thing I would suggest, is for both your IMA and print spooler service. Go to the properties of these, and set your print spooler to restart on failure. By default, these are set to "Take no action"