Citrix XenApp 6.5 Intermittent COM Port Redirection

We are experiencing intermittent COM port mapping issues with our electronic signature pads in our XenApp 6.5 farm runing HRP04. We map as follows:
net use com1: \\client\com4:

Most of the time the COM port maps successfully and the signature pad works fine. However, we are seeing occassional isues where the user tries to use the signature to sign it does not work. When this happens, we notice that Net Use cmd shows the COM1 as being unavailable. When we issue a 'net use com1: /delete' and attempt to re-map, we receive a 'system error 66'.

When we receive this error, a re-login to the same Citrix server does NOT resolve the issue. But if the user logs in and gets placed onto a different server, the COM port maps fine. After some time passes, we re-attempt to login to the original problematic Cirix server and the COM port resumes mapping again.

Any ideas?
Freda Driscoll-SbarDirector of System OperationsAsked:
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Sekar ChinnakannuStaff EngineerCommented:
Can you provide event log details on the time when users face issue and did you checked with network team for any delay occasionally? Also you try by installing the roll up pack 5 and check. To download
Freda Driscoll-SbarDirector of System OperationsAuthor Commented:
There is nothing in the Event logs. I am the network team. There is no latency at the time of occurrence. We are already on HRP05 actually.
Brian CTXSupportCitrix ConsultantCommented:
What hotfix level are your servers at?  Does it work via an RDP session?  Does it work for the users experiencing the issue sometimes, or does it always fail for those users?  Is there a specific server in the mix that's having the issue?  Is COM port mapping enabled via policy for some or all users?  Are any file redirection policies set?
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Freda Driscoll-SbarDirector of System OperationsAuthor Commented:
Citrix Version: 6.5 HR05
We have not replicated it in RDP mode yet. It is completely random and intermittent. It could affect one user on a given Citrix server with other users on same server being. Other times, it affects all users on a given Citrix server until they get placed onto a different Citrix server. However, re-login to problematic server later in the day the issues appears to resolve itself.

My Citrix forum thread:
My Spiceworks Thread:
Sekar ChinnakannuStaff EngineerCommented:
Any recent changes on the problematic server? If so try to remove the same and check. Check server load when users face the problem.
Freda Driscoll-SbarDirector of System OperationsAuthor Commented:
In Citrix the Net Use cmd shows the COM port redirection is listed as Unavailable. In RDP on the same server the COM port is missing and if we run 'net use com1: \\client\com4:' we get an system error 66

No changes have occurred on our Citrix servers recently other than applying Citrix HR05 and this issue has been occurring for a long time, just happening more frequently now.
Freda Driscoll-SbarDirector of System OperationsAuthor Commented:
It also appears that my Citrix AppCenter User Policy for AutoConnect COM ports and Enable COM port redirection is not applying to some Citrix servers. When I login to a Citrix server and perform a 'net use' cmd, it lists only the client drive mappings and NO COM port redirection/mappings....
Freda Driscoll-SbarDirector of System OperationsAuthor Commented:
1. I changed server to COM4 to match client COM4
2. I moved my Citrix XenApp User Policy for COM Port redirection and AutoConnect to top of policy list
3. Tests are so far consistently successful on one server out of 10...continued testing underway
Freda Driscoll-SbarDirector of System OperationsAuthor Commented:
We have been able to link the issue to the XenApp Hosted Client 12.3 and when we test the COM port redirection/mapping with the Receiver 4.2 client, it does NOT occur. This appears to be the fix for us. Further testing is underway...

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Freda Driscoll-SbarDirector of System OperationsAuthor Commented:
Resolved issue internally by upgrading Citrix client receiver to version 4.2 and issue was also related to XenApp Polices intermittently not applying to Citrix servers.
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