diff --git a/chrome/content/zotero/xpcom/cookieSandbox.js b/chrome/content/zotero/xpcom/cookieSandbox.js
index b54d380697..e17a7423fe 100755
--- a/chrome/content/zotero/xpcom/cookieSandbox.js
+++ b/chrome/content/zotero/xpcom/cookieSandbox.js
@@ -31,8 +31,9 @@
  * @param {String|nsIURI} uri URI of page to manage cookies for (cookies for domains that are not 
  *                     subdomains of this URI are ignored)
  * @param {String} cookieData Cookies with which to initiate the sandbox
+ * @param {String} userAgent User agent to use for sandboxed requests
  */
-Zotero.CookieSandbox = function(browser, uri, cookieData) {
+Zotero.CookieSandbox = function(browser, uri, cookieData, userAgent) {
 	this._observerService = Components.classes["@mozilla.org/observer-service;1"].
 		getService(Components.interfaces.nsIObserverService);
 	
@@ -54,6 +55,8 @@ Zotero.CookieSandbox = function(browser, uri, cookieData) {
 		}
 	}
 	
+	if(userAgent) this.userAgent = userAgent;
+	
 	Zotero.CookieSandbox.Observer.register();
 	if(browser) {
 		this.attachToBrowser(browser);
@@ -206,6 +209,10 @@ Zotero.CookieSandbox.Observer = new function() {
 				return;
 			}
 			
+			if(trackedBy.userAgent) {
+				channel.setRequestHeader("User-Agent", trackedBy.userAgent, false);
+			}
+			
 			// add cookies to be sent to this domain
 			channel.setRequestHeader("Cookie", trackedBy.cookieString, false);
 			Zotero.debug("CookieSandbox: Added cookies for request to "+channelURI, 5);
diff --git a/chrome/content/zotero/xpcom/server.js b/chrome/content/zotero/xpcom/server.js
index 1d7867c6bd..172a86c460 100755
--- a/chrome/content/zotero/xpcom/server.js
+++ b/chrome/content/zotero/xpcom/server.js
@@ -361,9 +361,12 @@ Zotero.Server.DataListener.prototype._processEndpoint = function(method, postDat
 		
 		// pass to endpoint
 		if((endpoint.init.length ? endpoint.init.length : endpoint.init.arity) === 3) {
+			const uaRe = /[\r\n]User-Agent: +([^\r\n]+)/i;
+			var m = uaRe.exec(this.header);
 			var url = {
 				"pathname":this.pathname,
-				"query":this.query ? Zotero.Server.decodeQueryString(this.query.substr(1)) : {}
+				"query":this.query ? Zotero.Server.decodeQueryString(this.query.substr(1)) : {},
+				"userAgent":m && m[1]
 			};
 			
 			endpoint.init(url, decodedData, sendResponseCallback);
diff --git a/chrome/content/zotero/xpcom/server_connector.js b/chrome/content/zotero/xpcom/server_connector.js
index 644d764359..7875f677b1 100755
--- a/chrome/content/zotero/xpcom/server_connector.js
+++ b/chrome/content/zotero/xpcom/server_connector.js
@@ -98,7 +98,7 @@ Zotero.Server.Connector.Detect.prototype = {
 	 * @param {Object} data POST data or GET query string
 	 * @param {Function} sendResponseCallback function to send HTTP response
 	 */
-	"init":function(data, sendResponseCallback) {
+	"init":function(url, data, sendResponseCallback) {
 		this.sendResponse = sendResponseCallback;
 		this._parsedPostData = data;
 		
@@ -115,7 +115,7 @@ Zotero.Server.Connector.Detect.prototype = {
 		var pageShowCalled = false;
 		var me = this;
 		this._translate.setCookieSandbox(new Zotero.CookieSandbox(this._browser,
-			this._parsedPostData["uri"], this._parsedPostData["cookie"]));
+			this._parsedPostData["uri"], this._parsedPostData["cookie"], url.userAgent));
 		this._browser.addEventListener("DOMContentLoaded", function() {
 			try {
 				if(me._browser.contentDocument.location.href == "about:blank") return;
@@ -283,7 +283,7 @@ Zotero.Server.Connector.SaveItem.prototype = {
 	 * @param {Object} data POST data or GET query string
 	 * @param {Function} sendResponseCallback function to send HTTP response
 	 */
-	"init":function(data, sendResponseCallback) {
+	"init":function(url, data, sendResponseCallback) {
 		// figure out where to save
 		var libraryID = null;
 		var collectionID = null;
@@ -293,8 +293,8 @@ Zotero.Server.Connector.SaveItem.prototype = {
 			var collection = zp.getSelectedCollection();
 		} catch(e) {}
 		
-		var cookieSandbox = data["uri"] && data["cookie"] ? new Zotero.CookieSandbox(null, data["uri"],
-			data["cookie"]) : null;
+		var cookieSandbox = data["uri"] ? new Zotero.CookieSandbox(null, data["uri"],
+			data["cookie"] || "", url.userAgent) : null;
 		
 		// save items
 		var itemSaver = new Zotero.Translate.ItemSaver(libraryID,
@@ -339,12 +339,12 @@ Zotero.Server.Connector.SaveSnapshot.prototype = {
 	 * @param {String} data POST data or GET query string
 	 * @param {Function} sendResponseCallback function to send HTTP response
 	 */
-	"init":function(data, sendResponseCallback) {
+	"init":function(url, data, sendResponseCallback) {
 		Zotero.Server.Connector.Data[data["url"]] = "<html>"+data["html"]+"</html>";
 		var browser = Zotero.Browser.createHiddenBrowser();
 		
 		var pageShowCalled = false;
-		var cookieSandbox = new Zotero.CookieSandbox(browser, data["url"], data["cookie"]);
+		var cookieSandbox = new Zotero.CookieSandbox(browser, data["url"], data["cookie"], url.userAgent);
 		browser.addEventListener("pageshow", function() {
 			if(browser.contentDocument.location.href == "about:blank"
 				|| browser.contentDocument.readyState !== "complete") return;