diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 0ffa2e2..fbee8ab 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -48,6 +48,11 @@ jobs:
       - name: Build
         run: cmake --build build -j$(nproc)
 
+      - name: Load virtual ALSA sequencer
+        run: |
+          sudo modprobe snd-seq || true
+          sudo modprobe snd-seq-dummy || true
+
       - name: Run tests
         run: ctest --test-dir build --output-on-failure
 
diff --git a/src/time/MtcTickSource.cpp b/src/time/MtcTickSource.cpp
index e84aea5..35bb586 100644
--- a/src/time/MtcTickSource.cpp
+++ b/src/time/MtcTickSource.cpp
@@ -14,6 +14,10 @@
 
 #include <climits>
 
+#ifdef __linux__
+#include <unistd.h>
+#endif
+
 namespace gme {
 namespace time {
 
@@ -37,9 +41,17 @@ MtcStartError MtcTickSource::start(const std::string& midiPort) {
     // MTC sources (e.g., rtpmidid) work without additional configuration (FR-002).
     MtcReceiver::setNetworkMode(true);
 
+    // Bail out early on Linux if the ALSA sequencer device is not present.
+    // This avoids an RtMidiError throw whose catch can silently fail when
+    // librtmidi's typeinfo address differs from the weak copy baked into
+    // static archives (RTTI mismatch across shared-library boundaries).
+#ifdef __linux__
+    if (access("/dev/snd/seq", F_OK) != 0) {
+        return MtcStartError::kNoPortsAvailable;
+    }
+#endif
+
     // Scan available ports for a name containing midiPort.
-    // RtMidiIn() throws RtMidiError when the ALSA/MIDI subsystem is absent
-    // (e.g., headless CI runners with no /dev/snd/seq).
     unsigned int portIndex = UINT_MAX;
     try {
         RtMidiIn probe;
@@ -55,6 +67,8 @@ MtcStartError MtcTickSource::start(const std::string& midiPort) {
         }
     } catch (const RtMidiError&) {
         return MtcStartError::kNoPortsAvailable;
+    } catch (...) {
+        return MtcStartError::kNoPortsAvailable;
     }
     if (portIndex == UINT_MAX) {
         return MtcStartError::kPortNotFound;
diff --git a/tests/bench_results/osc_latency.txt b/tests/bench_results/osc_latency.txt
index 8fdb4ac..9b87da5 100644
--- a/tests/bench_results/osc_latency.txt
+++ b/tests/bench_results/osc_latency.txt
@@ -1,8 +1,8 @@
 bench_osc_latency  N=1000  warmup=200
 
   A — synchronous lo_server       (spec SC-002 target p50≤1ms, p99≤5ms)
-    mean=0.005535 ms  p50=0.00545 ms [PASS]  p90=0.005481 ms  p99=0.006843 ms [PASS]  max=0.026129 ms
+    mean=0.005705 ms  p50=0.005421 ms [PASS]  p90=0.005811 ms  p99=0.01042 ms [PASS]  max=0.0478 ms
   B — lo_server_thread/OscServer  (production target p50≤5ms, p99≤20ms)
-    mean=0.009477 ms  p50=0.009037 ms [PASS]  p90=0.009438 ms  p99=0.017744 ms [PASS]  max=0.143061 ms
+    mean=0.009435 ms  p50=0.009067 ms [PASS]  p90=0.009729 ms  p99=0.021771 ms [PASS]  max=0.03686 ms
 
 RESULT: PASS