diff --git a/src/Backend/AutopilotMonitor.Functions/Services/TableStorageService.cs b/src/Backend/AutopilotMonitor.Functions/Services/TableStorageService.cs
index 657f9cc0..3a8d4d2b 100644
--- a/src/Backend/AutopilotMonitor.Functions/Services/TableStorageService.cs
+++ b/src/Backend/AutopilotMonitor.Functions/Services/TableStorageService.cs
@@ -447,7 +447,15 @@ namespace AutopilotMonitor.Functions.Services
                     if (status == SessionStatus.Succeeded || status == SessionStatus.Failed)
                     {
                         // Use the provided completedAt timestamp (from event) if available, otherwise use current time
-                        session["CompletedAt"] = completedAt ?? DateTime.UtcNow;
+                        var effectiveCompletedAt = completedAt ?? DateTime.UtcNow;
+                        session["CompletedAt"] = effectiveCompletedAt;
+
+                        // Store accurate DurationSeconds based on first event timestamp (not registration StartedAt)
+                        // The agent registers before events arrive, so registration StartedAt is always earlier
+                        // than the actual enrollment start — using the first event gives the true enrollment duration.
+                        var durationStart = effectiveEarliest ?? currentStartedAt;
+                        if (durationStart < effectiveCompletedAt)
+                            session["DurationSeconds"] = (int)(effectiveCompletedAt - durationStart).TotalSeconds;
                     }
 
                     // Set failure reason if failed
@@ -649,9 +657,10 @@ namespace AutopilotMonitor.Functions.Services
                 Status = status,
                 FailureReason = entity.GetString("FailureReason") ?? string.Empty,
                 EventCount = SafeGetInt32(entity, "EventCount") ?? 0,
-                DurationSeconds = completedAt.HasValue
-                    ? (int)(completedAt.Value - startedAt).TotalSeconds
-                    : (int)(DateTime.UtcNow - startedAt).TotalSeconds,
+                DurationSeconds = SafeGetInt32(entity, "DurationSeconds")
+                    ?? (completedAt.HasValue
+                        ? (int)(completedAt.Value - startedAt).TotalSeconds
+                        : (int)(DateTime.UtcNow - startedAt).TotalSeconds),
                 EnrollmentType = entity.GetString("EnrollmentType") ?? "v1",
                 DiagnosticsBlobName = entity.GetString("DiagnosticsBlobName")
             };
diff --git a/src/Web/autopilot-monitor-web/app/sessions/[sessionId]/page.tsx b/src/Web/autopilot-monitor-web/app/sessions/[sessionId]/page.tsx
index 4e982d79..f60ea535 100644
--- a/src/Web/autopilot-monitor-web/app/sessions/[sessionId]/page.tsx
+++ b/src/Web/autopilot-monitor-web/app/sessions/[sessionId]/page.tsx
@@ -1635,10 +1635,10 @@ function DeviceDetailsCard({ events }: { events: EnrollmentEvent[] }) {
           )}
 
           {/* System */}
-          {(bootTime?.bootTime || agentStarted?.bootTime || agentStarted?.agentVersion || imeVersion || aadJoinStatus?.joinType || deviceLocation?.country || deviceLocation?.Country || deviceLocation?.timezone || deviceLocation?.Timezone) && (
+          {(bootTime?.bootTimeUtc || bootTime?.bootTime || agentStarted?.bootTime || agentStarted?.agentVersion || imeVersion || aadJoinStatus?.joinType || deviceLocation?.country || deviceLocation?.Country || deviceLocation?.timezone || deviceLocation?.Timezone) && (
             <DetailSection title="System">
-              {(bootTime?.bootTime || agentStarted?.bootTime) && (
-                <DetailRow label="Boot Time" value={new Date(bootTime?.bootTime || agentStarted?.bootTime).toLocaleString()} />
+              {(bootTime?.bootTimeUtc || bootTime?.bootTime || agentStarted?.bootTime) && (
+                <DetailRow label="Boot Time" value={new Date(bootTime?.bootTimeUtc || bootTime?.bootTime || agentStarted?.bootTime).toLocaleString()} />
               )}
               {bootTime?.uptimeMinutes && <DetailRow label="Uptime until enrollment starts" value={`${Math.floor(bootTime.uptimeMinutes / 60)}h ${bootTime.uptimeMinutes % 60}m`} />}
               {agentStarted?.agentVersion && <DetailRow label="Monitor Agent Version" value={agentStarted.agentVersion.replace(/\+([0-9a-f]{7})[0-9a-f]+$/, '+$1')} />}