Now and again the controlling DLL file(s) for MSN becomes unregistered and MSN users receive MAILHOST and/or DOWNLOADHOST problem messages and can't connect to their mail. Many times this is caused by registry cleaning programs that incorrectly flag the MSN DLL files for deletion from the registry which effectively unregisters the files with the MSN software, resulting in the errors. Here's how to fix this. Note: If this happens once after running cleaning software it's likely to happen again if you run the same software again.

In both cases, to fix the problem(s) you need to re-register the files with the MSN program. To do this you will need to type a specific command into a run dialog. This command will register the DLL files with the MSN software and put the registry back in order.

If these commands do not work please contact MSN support. CKnow cannot directly support the MSN software.
MAILHOST

Click on the Start button. In the menu click on the entry that says Run. A dialog box will appear. Assuming a default installation of the MSN software, in the dialog box type (cut and paste from here for accuracy):

regsvr32 c:\progra~1\msn\msncorefiles\mailui.dll

Click on OK or press the Enter key. This re-registers the mailui.dll file and should solve the problem. If you are signed into MSN, sign out and then sign back in and everything should work OK.

If you have installed the MSN software in other than the default directory, then substitute that path for the c:\progra~1\msn\msncorefiles\ portion in the above.
DOWNLOADHOST

The problem and solution are similar to the above. Open the Run dialog as above but for DOWNLOADHOST type the following:

regsvr32 c:\progra~1\msn\msncorefiles\msnmetal.dll

This re-registers the msnmetal.dll file and should solve the problem. If you are signed into MSN, sign out and then sign back in and everything should work OK (though, some reports are that the error still pops up even though the downloading will work -- this may not be all that is needed).

If you have installed the MSN software in other than the default directory, then substitute that path for the c:\progra~1\msn\msncorefiles\ portion in the above.