Citrix has made some improvements when it comes to printing on XenApp 7.6. Coming from a XenApp 5.0 farm where the print spooler had to be restarted at least once a day, I’m glad to report no current issues exist in our XenApp 7.6 site. As noted in a previous post: XenApp 7.6 – ThinPrint .Print Engine – Printer Issues – Windows can not connect to the printer 0x00000057, printing issues in XenApp 5.0 could usually be traced back to incompatible print drivers. A solution that worked great in XenApp 5.0 and we later incorporated to our XenApp 7.6 site was the use of Cortado’s Thin Print V-Layer technology. V-Layer allowed us to virtualize all network printers on our print server and use only one driver supplied in ThinPrint, the TP OutPut Gateway Driver. This one driver was installed on all XenApp servers thus eliminating the need for native print drivers.
Driver incompatibility presented us with a challenge in XenApp 5.0 of not being able to support All-In-One Printers in a Citrix XenApp session. Organizations coming from a non-virtual computing solution sometimes find they have invested significantly in devices that may not necessarily be recommended in a Citrix XenApp environment. This was the case when we moved to XenApp 5.0 some time back. While replacing older PCs with thin clients, we found several of these had locally installed All-In-One printers. The use of All-In-One printers was a determining factor in whether or not a PC could be replaced with a thin client; the latter being preferred over a PC for for ease of deployment, management and reduction of IT support overhead.
On XenApp 7.6 I sought to address the need for supporting All-In-One printers by implementing Twain Redirection and configuring Auto-Create Client Printers.
For supporting printer functionality of All-In-One printers in XenApp 7.6, I have enabled Auto-Create Client Printers via a Citrix Policy. Auto-Create Client Printers maps printers that are installed locally on the client machine and makes them available to the user within the Citrix XenApp session. The printer, by default, is created using the Citrix Universal Printer driver. For most of our users, this has been disabled so as to minimize the possibility of printing issues due to the use of drivers other than the TP OutPut Gateway. One Citrix policy applied to all users in the Domain disables Auto-Create Client Printers. A separate policy was created that enables Auto-Create Client Printers. This second policy is placed higher up in the policies list to give it priority over the one that disables client printer auto-creation for everyone else. The policy that allows client printer auto-creation is applied only to a few users that have All-In-One printers installed locally on the client machine and is configured to auto-create the client’s default printer only .
For scanner support in XenApp 5.0 we had been using RemoteScan. RemoteScan server software and client software enabled the use of scanners for virtual environments. While it worked for the most part, we often had issues with the software loading too slow. Another problem was that scanners sometimes went undetected on the XenApp servers. And lastly, keeping track of licensing became a problem when re-purposing thin clients for use by other departments. Twain Redirection proved a viable and stable alternative in XenApp 5.0 and is what we have implemented in XenApp 7.6. Twain Redirection works with All-In-One Printers as the server OS is able to detect the scanner so long as the client machine has a Twain driver installed. A policy was created and Client Twain Device Redirection was set to Allowed. Twain Compression Level was configured to Medium.
Having created policies for Twain Redirection and Auto-Create Client Printers has allowed us to support All-In-One printer and scanner functionality in XenApp 7.6. Thus, we are no longer limited to which workstations can be replaced with thin clients. Still, due to system requirements, choosing the appropriate thin client is key when replacing a PC that has a locally installed All-In-One printer. The HP T620 thin client runs Windows 7 Embedded and has more resources than its predecessors, the HP T610 and HP T5740. HP T620 is what we are currently using. Remember to download and install basic Twain drivers for the All-In-One printers to use with thin clients and not the full software version. Lighter is better.
This problem may or may not be specific to Windows 7. In this case, Windows 7 embedded is installed on an HP T620 thin client. The user logs in to a web application using Internet Explorer 10 and Internet Explorer 11. On the web application, the user has access to PDF files that open in the IE browser. When trying to print a PDF from IE10 or IE11 web browser, the Printer dialog box appears corrupt and is unresponsive.
A workaround is to open Adobe Acrobat Pro > Edit > Preferences > Internet and uncheck Display PDF in browser. This will load the online PDF in Adobe Acrobat Pro 9 instead of the IE10/ IE11 web browser. However, if the user needs to interact with the PDF form in other ways other than just printing, such as signing the form with a signature pad or submitting it online, this workaround will have disabled that functionality. In that case, upgrading to a more recent version of Adobe Acrobat Pro will be required to fix the Acrobat Pro 9 online PDF Printing issue in IE10 and IE11 web browsers.