diff --git a/src/Propulsion.CosmosStore/CosmosStoreSink.fs b/src/Propulsion.CosmosStore/CosmosStoreSink.fs
index d9870b90..2904edff 100644
--- a/src/Propulsion.CosmosStore/CosmosStoreSink.fs
+++ b/src/Propulsion.CosmosStore/CosmosStoreSink.fs
@@ -121,7 +121,7 @@ module Internal =
                         struct (streams.SetWritePos(stream, pos'), false)
                     | Ok ((Writer.Result.Duplicate pos' | Writer.Result.PartialDuplicate pos'), _stats) ->
                         streams.SetWritePos(stream, pos') |> ignore // throw away the events (but not the unfolds)
-                        ValueNone, false // Don't declare progress
+                        ValueNone, false // Don't declare progress yet, until any unfolds have been handled
                     | Ok (Writer.Result.PrefixMissing _, _stats) ->
                         streams.WritePos(stream), false
                     | Error struct (exn, _stats) ->
diff --git a/tools/Propulsion.Tool/Sync.fs b/tools/Propulsion.Tool/Sync.fs
index af362f8b..875977bf 100644
--- a/tools/Propulsion.Tool/Sync.fs
+++ b/tools/Propulsion.Tool/Sync.fs
@@ -12,10 +12,11 @@ type [<NoEquality; NoComparison; RequireSubcommand>] Parameters =
     | [<AltCommandLine "-Z"; Unique>]       FromTail
     | [<AltCommandLine "-F"; Unique>]       Follow
     | [<AltCommandLine "-A"; Unique>]       RequireAll
+    | [<AltCommandLine "-E"; Unique>]       EventsOnly
     | [<AltCommandLine "-C"; Unique>]       Categorize
     | [<AltCommandLine "-b"; Unique>]       MaxItems of int
 
-    | [<AltCommandLine "-I";    AltCommandLine "--include-system"; Unique>] IncSys
+    | [<AltCommandLine "-N";    AltCommandLine "--exclude-system"; Unique>] ExcSys
     | [<AltCommandLine "-cat";  AltCommandLine "--include-category">]   IncCat of    regex: string
     | [<AltCommandLine "-ncat"; AltCommandLine "--exclude-category">]   ExcCat of    regex: string
     | [<AltCommandLine "-sn";   AltCommandLine "--include-streamname">] IncStream of regex: string
@@ -37,10 +38,11 @@ type [<NoEquality; NoComparison; RequireSubcommand>] Parameters =
                                             "NOTE normally a large `MaxReadAhead` and `cosmos -b` is required to avoid starving the scheduler. " +
                                             "NOTE This mode does not make sense to apply unless the ProcessorName is fresh; if the consumer group name is not fresh (and hence items are excluded from the feed), there will inevitably be missing events, and processing will stall. " +
                                             "Default: assume events arrive from the changefeed (and/or the input JSON file) without any gaps or out of order deliveries for any stream."
+            | EventsOnly ->                 "Exclude Unfolds from processing. Default: Unfolds are read, parsed and processed"
             | Categorize ->                 "Gather handler latency stats by category"
             | MaxItems _ ->                 "Limits RU consumption when reading; impacts checkpointing granularity by adjusting the batch size being loaded from the feed. Default (Sync): 9999. Default: Unlimited"
 
-            | IncSys ->                     "Include System streams. Default: Exclude Index Streams, identified by a $ prefix."
+            | ExcSys ->                     "Exclude System streams. Default: Include Index Streams, identified by a $ prefix."
             | IncCat _ ->                   "Allow Stream Category. Multiple values are combined with OR. Default: include all, subject to Category Deny and Stream Deny rules."
             | ExcCat _ ->                   "Deny  Stream Category. Specified values/regexes are applied after the Category Allow rule(s)."
             | IncStream _ ->                "Allow Stream Name. Multiple values are combined with OR. Default: Allow all streams that pass the category Allow test, Fail the Category and Stream deny tests."
@@ -56,9 +58,10 @@ and Arguments(c, p: ParseResults<Parameters>) =
     member val Filters = Propulsion.StreamFilter(
                                             allowCats = p.GetResults IncCat, denyCats = p.GetResults ExcCat,
                                             allowSns = p.GetResults IncStream, denySns = p.GetResults ExcStream,
-                                            includeSystem = p.Contains IncSys,
+                                            includeSystem = not (p.Contains ExcSys),
                                             allowEts = p.GetResults IncEvent, denyEts = p.GetResults ExcEvent)
     member val Categorize =                 p.Contains Categorize
+    member val IncludeUnfolds =             not (p.Contains EventsOnly)
     member val Command =
         match p.GetSubCommand() with
         | Kafka a ->                        KafkaArguments(c, a) |> SubCommand.Kafka
@@ -233,7 +236,10 @@ let run appName (c: Args.Configuration, p: ParseResults<Parameters>) = async {
             Some p
         | SubCommand.Stats _ | SubCommand.Sync _ -> None
     let isFileSource = match a.Command.Source with Json _ -> true | _ -> false
-    let parse = a.Filters.CreateStreamFilter() |> Propulsion.CosmosStore.EquinoxSystemTextJsonParser.eventsAndUnfoldsWhereStream
+    let parse =
+        a.Filters.CreateStreamFilter()
+        |> if a.IncludeUnfolds then Propulsion.CosmosStore.EquinoxSystemTextJsonParser.eventsAndUnfoldsWhereStream
+           else Propulsion.CosmosStore.EquinoxSystemTextJsonParser.whereStream
     let statsInterval, stateInterval = a.StatsInterval, a.StateInterval
     let maxReadAhead = p.GetResult(MaxReadAhead, if isFileSource then 32768 else 2)
     let maxConcurrentProcessors = p.GetResult(MaxWriters, 8)