I am working on .NET ClickOnce project that uses Sql Server 2005 Compact Edition to synchronize remote data through the use of a Merge replication. This application has been live for nearly a year now, and while we encounter occasional synchronization errors, things run quite smoothly for the most part.

Yesterday a user reported an error that I have never seen before and have yet to find any information for online. Many users synchronize every night, and I haven't received error reports from anyone else, so this issue must be isolated to this particular user / client machine. Here are the full details of the error:

-Error Code : 80004005
-Message : The message contains an unexpected replication operation code. The version of SQL Server Compact Edition Client Agent and SQL Server Compact Edition Server Agent should match. [ replication operation code = 31 ]
-Minor Error : 28526
-Source : Microsoft SQL Server Compact Edition
-Numeric Parameters : 31

One interesting thing that I've found is that his data does get synchronized to the server, so this error must occur after the upload completes. I have yet to determine whether or not changes at the server are still being downloaded to his subscription.

Thinking that maybe there was some kind of version conflict going on, I had a remote desktop session with this user last night and uninstalled both the application and the SQL Server Compact Edition prerequisite, then reinstalled both from our ClickOnce publication site. I also removed his existing local database file so that upon synchronization, an entirely new subscription would be issued to him. Still his errors continue.

I suppose the error may be somewhat general, and the text in the error message stating that the versions should match may not necessarily reflect the problem at hand.

This site contains the only official reference to this error that I've been able to find, and it offers no more detail than the error message itself.

Has anyone else encountered this error? Or at least know more about SQL Compact to have a better guess as to what is going on here? Any help / suggestions will be greatly appreciated!