SBS 2003 Microsoft Fax - "unable to re-register fxsroute.dll" and "Mail system DLL is invalid"

Posted on 2008-02-04
Medium Priority
Last Modified: 2013-12-27
Hi there.

I have performed all the steps in this document here:


It's still coming up with the error message of "Mail system DLL is invalid, when I try to route an already received fax job to exchange.

I have also gone and unregistered and re-registered all the .DLL files beginning with "FXS" in the C:\Windows\System32 directory. Some of which would never un-register or re-register (fxsroute.dll being one of these)

We had this problem fixed before by simply renamng the original fxsroute.dll to fxsroute.dll.old and copying the pre-SP2 fxsroute.dll into the system32 dir. This worked for a while and then died again once we moved to our new office.

Thanks for any help.
Question by:makingithappen
  • 2

Accepted Solution

Husbi earned 2000 total points
ID: 20820428

Author Comment

ID: 20946253
Hi there. Thanks a lot for this. It made some of the issues appear, like I couldn't telnet to localhost on port 25 to get the exchange prompts. Now thats been resolved, but even after I copied the FXSROUTE.DLL from the SBS CD#3 to the \Windows\System32 dir, it still wont register the file.

I've seen at the end of the list that the guy gets the file registered, all from enabling Anonymous access on the SMTP virtual server, but this hasn't happened for me.

Author Closing Comment

ID: 31427973
Hi there. The FXSROUTE.DLL never got registered, but the faxes started coming through this morning, after I modified the security permissions for anonymous logon for the Default SMTP Virtual server. Thanks for your help.

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