If the user account that the HIS services are configured to run under does not have permissions to the following registry key, the TN3270 service may terminate shortly after it starts:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\eventlog

When this occurs, an event message similar to the following is logged in the Application Event log:

Log Name:      Application
Source:        Application Error
Date:          date time
Event ID:      1000
Task Category: (100)
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      Computer Name

Description:
Faulting application tn3servr.exe, version 8.5.4430.2, time stamp 0x4ed963c0, faulting module tn3servr.exe, version 8.5.4430.2, time stamp 0x4ed963c0, exception code 0xc0000005, fault offset 0x000186af, process id 0x17d8, application start time 0x01cd2936bf6936aa.

The TN3270 Service is designed to terminate if the service is unable to load its event message file (tn3ntmsg.dll). The TN3270 event message file location and name is defined under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\eventlog\Application\TN3270 Server.

In the one reported instance where this problem occurred, the default permissions to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\eventlog had been changed to remove the Authenticated Users group which normally has Read access to this registry key.

The solution was to restore Read access to Authenticated Users group for this registry key so that the TN3270 service was able to load the event message file.