Merge agent failure-SQL Merge replication

Hi All, I have a a publisher which runs as a distributor and 4 subscribers. Using push merge replication. When I checked my replication monitor, I noticed that one subscriber was not synchronizing data showing the error messages below: The Merge Agent failed after detecting that retention-based metadata cleanup has deleted metadata at the Publisher for changes not yet sent to the Subscriber. You must reinitialize the subscription (without upload). (Source: MSSQL_REPL, Error number: MSSQL_REPL-2147199402) Get help: http://help/MSSQL_REPL-2147199402 I fear to reinitialize because I might lose the data entered at the subscriber after the error manifested. I have tried several advise from Google search but I have not got a solution yet. Kindly advise how I can solve this problem without losing data at the subscriber. Am using SQL Server 2005 and Win 2008. Thank you.