diff --git a/chrome/content/zotero/xpcom/integration.js b/chrome/content/zotero/xpcom/integration.js
index 035e3fdef..caff36868 100644
--- a/chrome/content/zotero/xpcom/integration.js
+++ b/chrome/content/zotero/xpcom/integration.js
@@ -89,6 +89,11 @@ Zotero.Integration = new function() {
 		// destroy old pipe, if one exists
 		try {
 			if(_fifoFile.exists()) {
+				if(_fifoFile.isSpecial() && Zotero.IPC.safePipeWrite(_fifoFile.path, "Zotero test\n")) {
+					Zotero.debug("Integration pipe already open by another instance; not initializing integration pipe");
+					return;
+				}
+				
 				_fifoFile.remove(false);
 			}
 		} catch (e) {
@@ -196,6 +201,8 @@ Zotero.Integration = new function() {
 	 */
 	function _parseIntegrationPipeCommand(string) {
 		if(string != "") {
+			if(string === "Zotero test\n") return;
+			
 			// exec command if possible
 			var parts = string.match(/^([^ \n]*) ([^ \n]*)(?: ([^\n]*))?\n?$/);
 			if(parts) {