diff --git a/src/main.zig b/src/main.zig
index 3577ac1..1ee54d3 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -5,6 +5,12 @@ const auth = @import("auth.zig");
 
 const version = @import("build_options").git_revision;
 
+fn exitAfterDelay() void {
+    std.Thread.sleep(500 * std.time.ns_per_ms);
+    std.log.err("Notmuch search is in unrecoverable state: exiting", .{});
+    std.process.exit(1);
+}
+
 pub fn main() !u8 {
     var gpa = std.heap.GeneralPurposeAllocator(.{}){};
     defer _ = gpa.deinit();
@@ -208,6 +214,13 @@ fn queryHandler(db: *root.NotmuchDb, req: *httpz.Request, res: *httpz.Response)
     const query = std.Uri.percentDecodeInPlace(query_buf);
 
     var threads = db.search(query) catch |err| {
+        if (err == error.CouldNotSearchThreads) {
+            res.status = 503;
+            try res.json(.{ .@"error" = "CouldNotSearchThreads", .fatal = true }, .{});
+            const exit_thread = std.Thread.spawn(.{}, exitAfterDelay, .{}) catch @panic("could not spawn thread to kill process");
+            exit_thread.detach();
+            return;
+        }
         res.status = 500;
         try res.json(.{ .@"error" = @errorName(err) }, .{});
         return;
diff --git a/static/index.html b/static/index.html
index 5516934..6c8cfee 100644
--- a/static/index.html
+++ b/static/index.html
@@ -48,6 +48,11 @@ button:disabled { background: #444; cursor: not-allowed; }
 .login-box h2 { margin-bottom: 1rem; }
 .login-box input { width: 100%; padding: 0.5rem; margin-bottom: 1rem; border: 1px solid #444; border-radius: 4px; background: #2a2a2a; color: #e0e0e0; }
 .login-box button { width: 100%; }
+.restart-overlay { display: none; position: fixed; top: 0; left: 0; width: 100%; height: 100%; background: rgba(0,0,0,0.9); z-index: 3000; align-items: center; justify-content: center; }
+.restart-overlay.visible { display: flex; }
+.restart-box { background: #252525; border: 1px solid #444; border-radius: 8px; padding: 2rem; text-align: center; }
+.restart-box h2 { margin-bottom: 1rem; color: #ff6b6b; }
+.restart-box p { margin-bottom: 1rem; color: #999; }
     </style>
 </head>
 <body>
@@ -107,6 +112,14 @@ button:disabled { background: #444; cursor: not-allowed; }
                 <button onclick="submitLogin()">Login</button>
             </div>
         </div>
+
+        <div id="restart-overlay" class="restart-overlay">
+            <div class="restart-box">
+                <h2>Server Restarting</h2>
+                <p>The server encountered a fatal error and is restarting...</p>
+                <p id="retry-countdown">Retrying in <span id="retry-seconds">5</span> seconds</p>
+            </div>
+        </div>
     </div>
     <script>
 let currentQuery = 'tag:inbox';
@@ -130,10 +143,32 @@ async function api(endpoint) {
         if (!retryRes.ok) throw new Error(`API error: ${retryRes.status}`);
         return retryRes.json();
     }
-    if (!res.ok) throw new Error(`API error: ${res.status}`);
+    if (!res.ok) {
+        if (res.status === 503) {
+            const data = await res.json();
+            if (data.fatal) {
+                showRestartOverlay();
+                throw new Error('Fatal server error');
+            }
+        }
+        throw new Error(`API error: ${res.status}`);
+    }
     return res.json();
 }
 
+function showRestartOverlay() {
+    document.getElementById('restart-overlay').classList.add('visible');
+    let seconds = 5;
+    const countdown = setInterval(() => {
+        seconds--;
+        document.getElementById('retry-seconds').textContent = seconds;
+        if (seconds <= 0) {
+            clearInterval(countdown);
+            location.reload();
+        }
+    }, 1000);
+}
+
 async function checkAuthStatus() {
     try {
         await api('auth/status');
