diff --git a/crates/syn2mas/src/migration.rs b/crates/syn2mas/src/migration.rs
index 4f6b78e0a..e4c92a8f5 100644
--- a/crates/syn2mas/src/migration.rs
+++ b/crates/syn2mas/src/migration.rs
@@ -414,7 +414,9 @@ async fn migrate_devices(
         // As we're using a real IP type in the MAS database, it is possible
         // that we encounter invalid IP addresses in the Synapse database.
         // In that case, we should ignore them, but still log a warning.
-        let last_active_ip = ip.and_then(|ip| {
+        // One special case: Synapse will record '-' as IP in some cases, we don't want
+        // to log about those
+        let last_active_ip = ip.filter(|ip| ip != "-").and_then(|ip| {
             ip.parse()
                 .map_err(|e| {
                     tracing::warn!(
diff --git a/crates/syn2mas/src/synapse_reader/mod.rs b/crates/syn2mas/src/synapse_reader/mod.rs
index 63e0719b4..30257657a 100644
--- a/crates/syn2mas/src/synapse_reader/mod.rs
+++ b/crates/syn2mas/src/synapse_reader/mod.rs
@@ -416,7 +416,7 @@ impl<'conn> SynapseReader<'conn> {
             SELECT
               user_id, device_id, display_name, last_seen, ip, user_agent
             FROM devices
-            WHERE NOT hidden
+            WHERE NOT hidden AND device_id != 'guest_device'
             ",
         )
         .fetch(&mut *self.txn)