SNALINK.EXE - Cancel Timeout in \driver\DLC (161768)

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256986 Description of the Microsoft Windows Registry

SYMPTOMS

When you stop the SNA Server service, the following error message may be displayed:

SNALINK.EXE - Cancel Timeout
The driver \driver\DLC failed to complete a cancelled I/O request in the allotted time.

After clicking OK, the same message may appear over and over again. You may not be able to perform any other operations until this error is cleared.

CAUSE

The error message is a Windows NT "hard error popup" which occurs if the SNA Server 802.2 link service terminates while the underlying DLC.SYS driver has completed IRP's to return to the calling thread. However, the link service has already ended. This error causes Windows NT to report a system-modal hard error popup which freezes the application subsystem until the user cancels the dialog. If multiple IRP's are completing, each IRP will cause another popup to appear.

This problem will only occur when the SNA Server service is stopped, which causes underlying SNA Server link services to stop too.

RESOLUTION

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While this error may occur during SNA Server shutdown, it is recommended that the hard error popup be suppressed by configuring the following Windows NT registry setting: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Windows\ ErrorMode: REG_DWORD: 2
The default is 0 which causes the error popup to appear, requiring the user to manually clear the error. This option is not recommended for Windows NT servers which may not be accessible to users. A value of 2 causes the error to be reported to the event log and returns OK to the hard error so the system can continue. Popups don't appear. This entry is described in the Windows NT 3.5 Resource Kit Volume 4 "Optimizing Windows NT", Appendix B on page 614.

STATUS

Microsoft has confirmed this to be an operational issue with Windows NT version 3.5, 3.51, and 4.0. It is recommended that the ErrorMode entry is modified for servers which aren't normally accessible to administrator personnel.