diff --git a/chrome/content/zotero/xpcom/streamer.js b/chrome/content/zotero/xpcom/streamer.js
index 6386cbe410..63278a902b 100644
--- a/chrome/content/zotero/xpcom/streamer.js
+++ b/chrome/content/zotero/xpcom/streamer.js
@@ -102,6 +102,28 @@ Zotero.Streamer_Module.prototype = {
 	},
 
 
+	/**
+	 * Remove the API key subscription before the key is deleted
+	 */
+	removeSyncSubscription: async function () {
+		if (!this._subscriptions.has('sync')) {
+			return;
+		}
+		let apiKey = this.apiKey || (await Zotero.Sync.Data.Local.getAPIKey());
+		if (!apiKey || !this._socket || this._socket.readyState !== this._socket.OPEN) {
+			this._subscriptions.delete('sync');
+			return;
+		}
+		let data = JSON.stringify({
+			action: 'deleteSubscriptions',
+			subscriptions: [{ apiKey }]
+		});
+		Zotero.debug("WebSocket message send: " + this._hideAPIKey(data));
+		this._socket.send(data);
+		this._subscriptions.delete('sync');
+	},
+
+
 	_sendSubscriptions: function (topics) {
 		let data = JSON.stringify({
 			action: "createSubscriptions",
@@ -140,7 +162,14 @@ Zotero.Streamer_Module.prototype = {
 			}
 		}
 		else if (this._subscriptions.has('sync')) {
-			subscriptionsToRemove.push({ apiKey });
+			if (apiKey) {
+				subscriptionsToRemove.push({ apiKey });
+			}
+			else {
+				// API key was cleared -- just remove local tracking.
+				// The server will clean up on reconnect.
+				this._subscriptions.delete('sync');
+			}
 		}
 		
 		if (Zotero.Prefs.get('automaticScraperUpdates')) {
diff --git a/chrome/content/zotero/xpcom/sync/syncRunner.js b/chrome/content/zotero/xpcom/sync/syncRunner.js
index fb19499efb..49aa089011 100644
--- a/chrome/content/zotero/xpcom/sync/syncRunner.js
+++ b/chrome/content/zotero/xpcom/sync/syncRunner.js
@@ -1683,6 +1683,8 @@ Zotero.Sync.Runner_Module = function (options = {}) {
 		this.resetStorageController('zfs');
 		var apiKey = await Zotero.Sync.Data.Local.getAPIKey();
 		var client = this.getAPIClient({apiKey});
+		// Remove streaming subscription before clearing the key
+		await Zotero.Streamer.removeSyncSubscription();
 		await Zotero.Sync.Data.Local.setAPIKey();
 		await client.deleteAPIKey();
 	}